Vitamin D is one of the most talked-about supplements of the last decade, and also one of the most misunderstood. Some people take far too little, a few take far too much, and many are confused by headlines that seem to change every year.

Here is the truth about vitamin D: what it is, how your body makes it, who tends to run low, what the best research actually shows, and how to raise your levels safely.

What Is Vitamin D?

Vitamin D is a fat-soluble vitamin that acts more like a hormone in the body. Your skin makes it when exposed to the sun’s ultraviolet B (UVB) rays, and you can also get it from food and supplements.

There are two main forms:

• Vitamin D3 (cholecalciferol): the form your skin makes and the form found in animal foods such as fish and egg yolks.
• Vitamin D2 (ergocalciferol): the form made by plants and fungi, such as UV-exposed mushrooms.

Your liver converts both forms into 25-hydroxyvitamin D, the form your doctor measures in a blood test. Your kidneys and other tissues then convert it into the active hormone, calcitriol. A meta-analysis of controlled trials found that vitamin D3 raises blood levels more effectively than D2, which is why most practitioners prefer D3.⁵ I covered newer research on this in Vitamin D3 vs D2.

The Truth About Vitamin D: 10 Facts Worth Knowing

1. Low vitamin D is common, especially in winter

A large share of adults have vitamin D levels below what most doctors consider ideal, and levels drop further in fall and winter. In much of the northern United States, the winter sun sits too low in the sky for your skin to make much vitamin D at all, no matter how long you are outside.

Fall and winter are also the seasons when colds and flu tend to spread, which is one reason researchers have looked so closely at vitamin D and immunity.

2. Modern life works against vitamin D

Our grandparents spent much of their day outdoors. Today most of us work, drive, and relax indoors. Factors linked with lower vitamin D levels include:

• Limited sun exposure: indoor jobs, long winters, and covering up outdoors.
• Darker skin: more melanin means the skin makes less vitamin D from the same amount of sun.
• Age: older skin makes vitamin D less efficiently, and older adults often spend less time outside.
• Digestive conditions: problems absorbing fat, such as celiac disease or Crohn’s disease, can reduce vitamin D absorption.
• Excess body weight: vitamin D is stored in fat tissue, so people with more body fat tend to have lower blood levels.
• Sunscreen: sunscreen is important for protecting your skin, and it also reduces vitamin D production.
• Few food sources: very few foods naturally contain much vitamin D.

3. Vitamin D is often lower in people who are overweight

Because vitamin D is fat-soluble, it gets distributed into fat tissue. When there is more fat tissue, the vitamin D in your body is spread across a larger volume, so blood levels tend to read lower. People carrying extra weight often need more vitamin D to reach the same blood level.

The good news is that healthy weight loss tends to help. If that is a goal for you, my article on how you can lose weight with a ketogenic diet is a good place to start.

4. The recommendations have changed, and they changed again in 2024

This is where much of the confusion comes from. In 2011, the Endocrine Society published a guideline that defined deficiency as a blood level below 20 ng/mL and suggested aiming for at least 30 ng/mL.² For more than a decade, many doctors used 30 ng/mL as the target.

In 2024, the Endocrine Society issued a new guideline focused on preventing disease in people without a known vitamin D problem.¹ The key changes:

• For most healthy adults under 75, it recommends getting the standard daily intake from the Institute of Medicine (600 IU for adults up to 70 and 800 IU over 70), rather than higher doses.
• It suggests extra vitamin D for certain groups: children and teens, adults over 75, pregnant women, and adults with prediabetes.
• It no longer recommends routine vitamin D blood testing for healthy people and does not endorse a specific target blood level.

My recommendation is different. In my practice, I recommend 5,000 to 10,000 IU of vitamin D3 a day for most adults, taken with a meal and with vitamin K2. For patients with weakened immunity, I may use 20,000 IU a day for a period of time. These amounts are above the official upper limit of 4,000 IU a day, so take them with your own doctor’s guidance, get your 25-hydroxyvitamin D level checked before you start, and recheck it so your level stays in a healthy range.

5. Vitamin D may modestly support respiratory health

Researchers have run dozens of trials on vitamin D and respiratory infections. A 2017 analysis in the BMJ, which pooled individual data from about 11,000 participants in 25 trials, found that vitamin D supplementation reduced the risk of acute respiratory infections overall, with the biggest benefit in people who started out with very low levels.³

An updated 2021 meta-analysis that added newer trials found a smaller but still statistically significant protective effect. Importantly, the benefit showed up with daily doses, not with large occasional “bolus” doses.⁴

So the honest summary is this: vitamin D is not a magic shield, but steady daily intake that corrects a shortfall may modestly support your body’s defenses, especially if you were low to begin with.

6. Vitamin D plays a direct role in the immune system

Many immune cells carry vitamin D receptors and can activate vitamin D themselves. Vitamin D helps the body produce antimicrobial peptides, such as cathelicidin, which are part of the first line of defense. It also helps balance inflammatory signaling. This is why vitamin D status matters for overall immune function.

7. Vitamin D is essential for bones and muscles

Vitamin D helps your gut absorb calcium and phosphorus. Without enough of it, the body pulls calcium from the bones, which over time weakens them. Severe deficiency causes rickets in children and osteomalacia (soft bones) in adults. Adequate vitamin D also supports normal muscle function, which matters for balance and fall prevention as we age.

8. Vitamin D is not a cure-all

Low vitamin D has been linked in observational studies with many chronic health problems, as well as low moods. But linked is not the same as caused. Poor health can also lower vitamin D, for example by keeping people indoors.

The large VITAL trial gave about 25,000 generally healthy adults 2,000 IU of vitamin D3 daily or a placebo for about five years. Vitamin D did not lower the overall rates of cancer or heart attack and stroke compared to placebo.⁶ For most people, the goal is to avoid deficiency, not to expect a high dose to prevent disease on its own.

9. Your body makes vitamin D from sunlight, but it may not be enough

Sensible sun exposure is the most natural source of vitamin D. In the warmer months, many people with lighter skin can make a meaningful amount with about 10 to 15 minutes of midday sun on the arms and legs a few times a week, while people with darker skin need longer. Be careful never to burn.

In winter, at northern latitudes, or if you spend most of your day indoors, sunlight alone often will not keep levels where they should be. Spending more time outside has other benefits too. See my article on daylight and dementia risk.

10. More is not always better

Because vitamin D is stored in the body, it is possible to take too much. The upper limit set by the Institute of Medicine for adults is 4,000 IU per day unless your doctor prescribes more for a specific reason. Vitamin D toxicity is rare and almost always comes from taking very high doses over a long period.

The main problem with too much vitamin D is a buildup of calcium in the blood (hypercalcemia), which can cause nausea, vomiting, weakness, confusion, frequent urination, and over time kidney stones and kidney damage. If you take more than the standard amount, ask your doctor to check your blood levels.

How to Raise Your Vitamin D Levels Naturally

If your levels are low, here are practical steps:

• Get outside. Enjoy brief, regular midday sun in the warmer months, without burning.
• Eat vitamin D foods. Fatty fish such as wild salmon, sardines, herring, and mackerel are the best food sources. Egg yolks and UV-exposed mushrooms add smaller amounts. Try my Keto Zone salmon chowder.
• Work toward a healthy weight. This can help your body make better use of the vitamin D you get.
• Consider a supplement. If you supplement, D3 is the preferred form, and taking it with a meal that contains fat helps absorption. A quality multivitamin can also cover the standard daily amount. For example, Dr. Colbert’s Enhanced Multivitamin provides 800 IU of vitamin D3 along with vitamin K2. Read more in 10 Reasons to Take a Daily Multivitamin.
• Talk with your doctor about whether testing makes sense for you, and before taking higher doses.

Bottom Line

Vitamin D is a remarkable vitamin and hormone that supports your bones, muscles, and immune system. Low levels are common, especially in winter, in older adults, in people with darker skin, and in those carrying extra weight. The newest guidelines encourage most healthy adults to simply meet the standard daily intake, while certain groups may need more. Get some safe sun, eat vitamin D foods, keep doses sensible, and work with your doctor if you think you may be low.

For more ways to stay strong as you age, visit my Healthy Aging Start Here guide.

Frequently Asked Questions

What is a normal vitamin D level?

Most labs report 25-hydroxyvitamin D in ng/mL. Below 20 ng/mL is widely considered deficient, and many doctors have used 30 ng/mL as a minimum goal. The 2024 Endocrine Society guideline does not set a specific target, so ask your doctor what level is right for you.

How much vitamin D should I take daily?

The official recommended intake is 600 IU per day for adults up to age 70 and 800 IU over 70, with an upper limit of 4,000 IU unless your doctor prescribes more. Dr. Colbert recommends 5,000 to 10,000 IU of vitamin D3 a day for most adults, with vitamin K2, and up to 20,000 IU for a period of time for people with weakened immunity, with a doctor’s guidance and blood tests to monitor levels.

Is vitamin D3 better than D2?

Research shows vitamin D3 raises blood levels more effectively than vitamin D2, which is why most practitioners prefer D3 for supplements.

What are the signs of low vitamin D?

Many people with low vitamin D have no obvious symptoms. When symptoms do occur, they can include fatigue, bone pain, muscle weakness or aches, and low mood. A blood test is the only way to know your level.

Can you get enough vitamin D from the sun?

In the warmer months, many people can make a good amount with short, regular periods of midday sun. In winter, at northern latitudes, with darker skin, or if you are mostly indoors, sunlight alone often is not enough.

Can you take too much vitamin D?

Yes. Taking very high doses for a long time can raise blood calcium too high, which can cause nausea, weakness, frequent urination, and kidney problems. If you take more than 4,000 IU a day, do it with your doctor’s guidance and periodic blood tests.

References

1. Demay MB, et al. Vitamin D for the prevention of disease: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2024.
2. Holick MF, et al. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2011.
3. Martineau AR, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017.
4. Jolliffe DA, et al. Vitamin D supplementation to prevent acute respiratory infections: a systematic review and meta-analysis of aggregate data from randomised controlled trials. Lancet Diabetes Endocrinol. 2021.
5. Tripkovic L, et al. Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis. Am J Clin Nutr. 2012.
6. Manson JE, et al. Vitamin D supplements and prevention of cancer and cardiovascular disease. N Engl J Med. 2019.

This article is for educational purposes only and is not medical advice. Talk with your own doctor before changing your diet, starting a supplement, or changing any medication. These statements have not been evaluated by the Food and Drug Administration. Products mentioned are not intended to diagnose, treat, cure, or prevent any disease.

The post The Truth About Vitamin D: 10 Facts on Levels, Benefits and Safety appeared first on Dr. Don Colbert, MD.

If not, we have a cheat sheet for you. Here are 12 Daily Healthy Immune Habits that are easy to implement starting today. Moreover, here’s how simple habits affect immune function both positively and negatively.

How Can Habits Support Immune Function?

There are a few different ways lifestyle habits can affect immune function.

First, they can reduce inflammatory actions and oxidative stress in the body. Next, they can activate immune cells directly. Third, they can indirectly affect your immunity. For example, high blood sugars are associated with increased infection risk (1), while controlled ones are not.

Lastly, and on the other side, they can negatively impact immune function by diminishing the health of immune cells or degrading the body’s overall health.

Your daily habits matter. Throughout each day, you can choose to support your immune function. Make your habit choices wisely.

12 Daily Healthy Immune Function Habits

1. Gratitude When You Wake

How can you prioritize your health and immune function right when you wake up? You can be purposeful to start the day with gratitude. Whatever lies ahead in your day, you can be grateful for something or someone to start.

How does this support immune health?

Gratitude is one of our daily immune support habits because it can reduce stress and cortisol. Cortisol increases inflammation in the body. What’s more, gratitude can improve sleep while reducing stress.

A study of 400 individuals found that writing gratitudes during the day and/or before sleep improves both the quality and duration of sleep (1). Another study found that gratitude was linked to a 10% improvement in sleep and a 19% decrease in sadness levels in patients with health issues and insomnia (2).

For an extra boost, combine your time of gratitude with meditation. Focus on the moment, the day, and those things for which you are grateful. Be present in these thoughts, not thinking ahead or behind. Incredibly, this sort of mindful meditation can stimulate the immune system. Its benefits include improvements in specific markers of inflammation, cell-mediated immunity, and biological aging (3).

2. Ice-Cold Shower for Better Immune Function

Not everyone enjoys an ice-cold shower or burst of cold water in the morning. But for those who can stand it, it will support immune health!

How?

First, cold showers are linked to an improved immune system. A recent study from the Netherlands found that cold showers significantly reduced sick days in workers. In fact, 30 seconds or more of cold showering per day reduced sick days by 29% in the study. Additionally, more than half the participants decided to continue the cold-shower practice after the study since they were convinced by the results (4).

Why would cold water improve immunity? It’s thought that cold-water-stress induces the production of catecholamines, which may play a critical role in supporting the immune system.

3. Take Your Vitamins

Specific vitamins, minerals and compounds support your immune function. While you can certainly eat foods that do so as well, supplements can bolster immunity with larger amounts of isolated nutrients. Specific immune-supporting nutrients include vitamin C, B-vitamins, elderberry, zinc, and vitamin D3 (5, 6).

If you’re looking for a one-stop-shop for all of these compounds, try this supplement. Dr. Colbert’s Immune Support contains each one in amounts designed to support your immune system best.

4. Get Outside into the Sunshine Early

There are many benefits to getting outside. And, the earlier you do it, the better. Sunshine and time outdoors both support immune health, for free! They:

• Increase vitamin D production: Optimal vitamin D levels are associated with fewer seasonal illnesses. What’s more, optimal vitamin D levels support health throughout the body, from bones to skin to organs
• Improve melatonin levels, especially if you’re out in the early hours after waking. Why does this matter for immune function? Optimal melatonin improves sleep, and sleep is directly beneficial to the immune system
• Improve mood, which decreases cortisol to support healthy immune function

Get outside whenever you can, and aim for early hours if possible.

5. Daily Hydration for Health and Reduced Cortisol

Did you know that fluid restriction and dehydration may increase cortisol in your body? This becomes especially true if you are participating in an outdoor activity (7).

To reduce cortisol and therefore inflammation, hydrate your body regularly.

As a bonus, you’ll promote overall cell health and skin. One recent study has shown that increasing water consumption by 2 liters per day improved skin condition and physiology, even in those who already consumed high amounts of water. The researchers concluded that this increase and improvement in skin health would likely have the most positive effect on those with lower daily water consumption (8).

If you want to take the immune and health benefits even further, drink green tea for part of your daily hydration.

6. Meals with Immune Supporting Foods

Throughout the day, choose foods that are anti-inflammatory and full of antioxidants. Vibrant fruits and vegetables, healthy fats, nuts, spices, and protein often fit the bill. Specific foods include:

• Fish and seafood
• Healthy fats such as extra virgin olive oil, avocados, MCT oil powder, and more
• Vibrant vegetables and small amounts of fruits
• Cacao, spices, and herbs such as ginger, garlic, basil, and more
• Potent greens and herbs like spirulina, wheatgrass, milk thistle, and more

Great foods can be delicious and promote healthy immune function!

7. Move Your Body

Exercise provides a powerful 3-punch combination of immune function, health, and healthy aging. It:

1. Modulates antioxidant and anti-inflammatory effects in the body by supporting neuroprotective action, increasing circulating of anti-inflammatory markers, and improving antioxidant defenses (9).
2. Promotes overall body composition and healthy weights. Unhealthy weights are associated with a decline in immune function.
3. Decreases blood glucose. High blood sugars are linked to worsened infections (1).

8. Laugh and Enjoy Healthy Relationships

What do healthy relationships and laughter have to do with immune function and overall health?

Incredibly, the Harvard Study of Adult Development has shown that good social relationships promote physical and mental health, provide a buffer against loneliness, increase longevity, and foster happiness.  The Harvard Nurses’ Health Study found similar results. This means less anxiety and cortisol, and better health outcomes.

Next, laughter further reduces cortisol, increases dopamine, and increases endorphins. These chemicals decrease discomfort, cortisol (10), and depressed moods (11) while elevating cellular health.

9. Starting Mid-Evening, Employ Intermittent Fasting

Around 7 pm in the evening, consider starting a daily intermittent fast to support your health and immune function.

Amazingly, there are many documented benefits to intermittent fasting including:

• Immune function support (12)
• Improve cholesterol markers*
• Reduced triglyceride levels*
• Improved aging*
• Healthy weight changes without negative cellular adaptations*
• Reduced blood sugar abnormalities*

In fact, many studies have shown that intermittent fasting supports healthy aging, brain health, heart health, and blood sugars (13).

To add intermittent fasting to support immune health, aim to fast 15-16 out of the 24 hours per day. Simply finish eating dinner at 7 pm each night, and fast with only non-carbohydrate liquids (like coffee) until 10 am or so.

10. Sleep: 7 or More Hours Per Night

Good quality sleep has many health and aging benefits. These include:

• Reduced daily cortisol*
• Healthy immune function*
• Better melatonin levels*
• Less depressed moods*
• Less inflammatory reactions*
• Healthy body weight*
• Healthy heart function*

It’s a cycle. Good sleep begets good sleep, and lack of sleep increases cortisol for up to 24 hours which negatively affects sleep again (14). Lack of sleep has also been shown to reduce mental performance and alertness while increasing inflammation and cortisol (15).

11. De-Stress Before Bed

Amazingly, stress and high cortisol levels can negatively affect immune function and response (22). You can fight back with an amazing all-natural stress-reducing oil.

Hemp oil, specifically nano-particle hemp oil, promotes health across the body’s systems while combatting stress. In fact, it’s nature’s best stress relief.

It is a broad-spectrum hemp oil that is organically grown, vegan, and GMO-free. In terms of health, it have been shown to:

• Support healthy, stable moods (16)
• Promote stress relief and normalized cortisol levels
• Support comfortable, healthy joints (17)
• Encourage healthy sleep habits (18)
• Promote healthy skin with fewer irregularities and blemishes (19)
• Support healthy brain and nervous system functions (20) 
• Encourage healthy cardiovascular functions and normalized inflammatory actions (21)

12. Fast from from Detrimental Foods and Detox the Body Regularly

Here’s another healthy habit with a big punch! Get rid and detox from the foods that have a negative effect on health and immune function.

It’s time to reduce sweets, sugars, and refined carbohydrates, omit processed food fats like soybean oil, and help your body detox from the build-up of toxins and chemicals. How?

The easiest and most effective way is to follow the Keto Zone Diet. In fact, Dr. Colbert’s Gut Zone Book provides a complete road map to reducing these foods, achieving a healthy weight, and supporting healthy immune function.

Bottom Line

Ready to support immune health every day? You can do it! These easy healthy immune function habits can be implemented together, or one at a time. Focus each day on your immune system and promote health throughout your body!

The post 12 Easy Daily Healthy Immune Habits appeared first on Dr. Don Colbert, MD.

The principles of Keto Zone eating improve overall health, gut health, brain health, and immune function.

Here are 5 ways to boost immunity with Keto Zone.

Top 5 Ways to Boost Immunity with Keto Zone

1. Boost Immunity with Keto Healthy Gut Bacteria

Healthy gut bacteria have a direct impact on the whole body’s immune function. When they are diminished from illness, antibiotics, or other conditions, the immune system suffers.

When they proliferate, the immune system improves (1).

To boost immunity with Keto Zone, eat fermented foods that can improve your gut bacteria. These include:

• Plain yogurt
• Kimchi
• Sauerkraut
• Kefir
• Kombucha
• Tempeh
• Fermented vegetable powders, like Fermented Green Supremefood
• Living foods, like chia seeds
• Probiotic supplements

Do fermented foods really help the bacteria in the gut?

Studies show that people who eat yogurt regularly have more  lactobacilli (healthy bacteria) and less Enterobacteriaceae (inflammatory bacteria) in their intestines (2).

What’s more, probiotic supplements contain live, viable probiotic bacteria in pill or powder form. These supplements are especially beneficial to humans who have digestion issues, such as Irritable Bowel Syndrome, frequent loose stools, constipation, and more. Typically, probiotics supplements don’t provide a permanent cure to digestion issues, nor do they colonize in the gut permanently.

However, both anecdotal reports and studies show they help acute digestion symptoms. They can also produce beneficial effects on the bacteria in the gut (3).

2. Reduce Inflammation with Omega-3s, Spices, and Low-Carb Keto Zone Eating

Did you know that inflammation is an abnormal immune response that affects the health of the digestive tract (which affects immune function) and whole-body health (1).

Our bodies react with inflammatory responses or anti-inflammatory responses based largely on our health and our diet.

You can use Keto Zone to reduce inflammatory responses and improve the immune system.

How?

First, reduce inflammation by removing high-sugar and high-carbohydrate foods.

Second, increasing your intake of omega-3 foods such as fatty fish, hemp heart seeds, flaxseeds, chia seeds, and others can reduce inflammation

Third, including highly anti-inflammatory spices like turmeric, ginger, cinnamon reducing inflammatory responses.

Fourth, use Keto Zone guidelines to reduce processed foods. Processed foods are often laden with high-omega-6 oils, like soybean oil. These ingredients and oils fight omega-3s and increase inflammation.

As you follow these guidelines, you can reduce inflammation, improve immune function, and even reduce the risk of seasonal depression (4).

3. Eat Less Sugar and Carbs for Better Sleep

There are many advantages to reducing sugars and carbohydrates in the diet. Two are better sleep and better metabolic responses.

When dinners are high in sugary and refined carbs, our bodies have to deal with blood glucose and insulin spikes at a time of day they are not meant to deal with it.

At night, our bodies don’t want to digest and metabolize foods. In fact, late eating, and high carb0hydrate eating during the evening and night are associated with altered metabolism, increased incidence of diabetes, and weight gain (5).

When you don’t eat as much as night, especially carbohydrates and sugars, you can allow your digestive tract to “rest,” and sleep better.

The science is clear: Adequate, high-quality sleep is crucial for immune function, fighting chronic disease, and brain health (6).

4. Focus on Keto-Friendly Vitamin D

Vitamin D plays an important role in immune function. During months when most people don’t receive enough direct sunlight (Autumn and Winter), it’s time to make sure our diets and supplements are high in vitamin D.

In fact, a 2017 analysis of 11,321 participants in the British Medical Journal found that those with vitamin D levels of <10 ng/mL had a higher risk of respiratory infections compared to those at 10 ng/mL or greater (7).

To improve vitamin D levels, make sure you’re:

• Getting outside for direct sunlight exposure to start. Try exposing skin for just 10-15 minutes per day.
• Eating wild fish such as herring, wild salmon (try this Keto Zone chowder recipe), and tuna. Cage-free eggs and cheese also supply small amounts.
• If overweight, using Keto Zone guidelines to lose weight.
• Supplementing vitamin D3 as needed. Just 1000-2000 IU per day in the winter can raise insufficient levels, and up to 4000 IU per day can be used to correct a deficiency. Retest to monitor.

5. Use Supremefoods to Boost Immunity and Healthy Bacteria

Fermented vegetables, grasses, and fruits are full of vitamins, minerals, and nutrients that boost immune function.

When eating low carb, it can be difficult to find ways to include enough. A great way to consume them, and stay in the Keto Zone, is with Divine Health Fermented Green Supremefood and Organic Red Supremefood.

Supremefoods powders contain amazing ingredients such as:

• Spirulina: Spirulina has been found to improve immune functions and anemia status (8).
• Beets: Beets contain betanins that contribute to three main disease-fighting actions: fighting free radicals, reducing inflammation, and supporting cellular detoxification (9, 10).
• Fermented Wheatgrass: Proteins found in wheatgrass are known to prevent many diseases, oxidative stress, primary metabolism, storage, and energy-related mechanisms (11).

More Ways to Stay Healthy:

1. Hydrate Every Day.  Your body needs water to function its best. Dehydration will affect your energy, immune and lymph systems, and overall health. Drink water, unsweetened teas, and other fluids throughout the day especially during dry winter months.
2. Get outside. When you spend time outside, bundled if needed, you can get a boost in vitamin D, and get away from all the germs that circulate indoors. In fact, just exposing your hands and face to sunlight allows your body to synthesize vitamin D. Make it a priority this winter.
3. Wash your hands and avoid touching your face. You get sick for one reason (and one reason only): germs. Bacteria and viruses make you ill by finding a way into your body through physical contact. Once this happens, it’s important having a strong immune system as discussed above. Since most of your contact with the world happens through your hands, washing them often is one key to not getting sick.

Bottom Line

You can boost immunity with Keto Zone. Keto Zone encourages whole-food, anti-inflammatory, high-antioxidant, low-carb eating. Its recommendations are meant to boost whole-body health, and it can help keep you healthy year-round.

The post Top 5 Ways to Boost Immunity with Keto Zone appeared first on Dr. Don Colbert, MD.

Notably, there is a direct and measurable improvement in immune function outcomes and the incidence of sickness during and after healthy weight changes. It will take work and dedication to improve your weight. We are here to help and have a plan that will guide you towards a healthy weight and lifestyle. Are you ready to support your immune function with a healthier weight?

Unhealthy Weight And Incidence of Sickness

During the past few decades, experts have come to understand that being at an unhealthy weight, directly and indirectly, increases the risk of seasonal sickness and poor immune function.

In fact, they believe that being overweight can cause a chronic state of inflammation that harms immune function. This can result in a blunted immune response to harmful invaders and microbes, poor recovery, and even a decreased response with medications (1).

As the number of overweight individuals continues to increase in the population, health experts are bracing for more and more community sickness.

But, there’s good news.

Even just a small change in weight or a loss of about 5-10% can make a big difference in immune function. And, the more an individual moves towards a healthy weight, the better the results become.

Here are 5 ways a healthy weight supports immune function.

5 Ways a Healthy Weight Supports Immune Function

1. Healthier Gut Bacteria and Reduced Inflammation

Did you know that gut microbiota (bacteria) is altered in an overweight or obese individual compared to one at a healthy weight? It’s true. It’s in an unhealthy state.

This unhealthy state has big implications for immune function and overall health. Human gut bacteria plays many roles, and an immune function is highly dependent on it. What’s not so clear is whether being obese causes healthy bacteria to change and become unhealthy, or whether the altered gut bacteria contribute to obesity.

Experts believe the answer is a bit of both. There are several mechanisms linking the gut microbiota with obesity, altered insulin reactions, inflammation, metabolic issues, failing liver function, and more. The unhealthy gut bacteria may actually contribute to an altered hormone state that perpetuates fat gain (2). More fat gain further deteriorates healthy gut bacteria. This unhealthy cycle continues and reaps havoc on immune function.

So, how does a healthy weight affect the gut and immune system? As an individual works towards and achieves a healthy weight,  there are significant changes in gut microbial composition. These changes continue to spur advances toward a healthy weight. This is true for both diet-induced weight changes and bariatric surgery (3). Adding healthy bacteria to the diet during the effort can further support digestion and immune function.

2. Normalized Blood Sugars with a Healthy Weight

Did you know the presence of high blood sugars increases the incidence of sickness and infection? Thankfully, a healthy weight can normalize blood sugars.

In fact, when blood sugars are high, sickness can induce a stress reaction which may lead to the secretion of hyperglycemic hormones, abnormal glucose variability, and health complications. What’s more, infections increase blood sugar levels which perpetuates the problem.

The opposite is true when an individual works towards a healthy weight. In one study, researchers reported that improvements in weight were strongly associated with improvements in blood sugars, blood pressure, triglyceride levels, and HDL cholesterol. They stated that a modest weight loss of just 5-10% was enough to improve health (4).

3. Healthy Weight Means a Healthier Heart

Another organ vital to overall health and immune function is the heart.

Unfortunately, obesity is associated with an increased risk of developing cardiovascular illnesses. Why? Being overweight stresses the heart, and this can lead to increased inflammation, elevated blood pressure, and changes in heart structure. What’s more, pro-inflammatory cytokines produced by adipose tissue can induce cardiac dysfunction (5).

On the other hand, most illnesses can hurt the heart, and harmful microbes can promote the development of cardiovascular disorders and injury. An unhealthy or weak heart diminishes immune strength (6). 

Achieving a healthy weight supports immune function and heart health!

4. A Healthy Weight Promotes a Healthier Liver

5. Healthy Lungs

How to Work Towards a Healthy Weight Starting Today

If you are interested in supporting your immune system and overall health by achieving a healthy weight, we have plans for you!

In fact, you can start with Dr. Colbert’s 21 Day Detox and Fast. It’s free and will help you improve the health of every system mentioned here.

Then, you can make real lifestyle changes and achieve a healthy weight with Keto Zone. Start by joining our FREE Keto Zone 21-Day-Challenge. Next, keep going with the Keto Zone Starter Kit including Dr. Colbert’s Keto Zone Diet Book and his latest book, Healthy Gut Zone, as approximately 75 percent of your total immune cells are found in your gut.

Bottom Line

You can support your immune system, but it takes working towards a healthy weight. Work towards your goals, and let us help with proven programs for health, immunity, and lifestyle change! You can start for free today!

The post 5 Ways A Healthy Weight Supports Immune Function. Achieve Yours. appeared first on Dr. Don Colbert, MD.

These healthy habits are science-backed methods to support immune function. Here’s how you can use each one to lift your mood, your faith, and your immune system today.

8 Easy Lifestyle Habits for Your Immune System’s Health

1. Laugh as Much as Possible

Let’s start with a joyful habit. Laughter.

Have you ever wondered why we laugh? Why did God give us this gift?

It is an amazing health-promoting habit. The more you can build laughter into your daily life, the more you’ll reduce cortisol, improve your mood, and decrease depression.

These, in turn, will encourage healthy immune function.

Interestingly, multiple studies show that the benefits of smiling and laughter are experienced whether its real or fake. So, fake it if you need to, and get in a good belly laugh each day.

2. Sleep at Least 7 Hours Per Night

Sleep is one of the strongest immune-boosters available to you. It can support your immune function through your lymph system and help your body restore itself each day.

How is sleep one of the strongest lifestyle habits for healthy immune function?

It allows your body and brain to recoup, restore, and fight disease. During sleep, your immune system releases cytokines which both promote sleep and fight disease. When you are awake, your body must do the work of being awake, moving, and maintaining an active brain. This takes most of its resources. When you are asleep, it can do maintenance on your body.

What’s more, sleep deprivation is well-documented as a factor in decreased immunity and increased illness, decreasing immune cells in number and strength (1).

One study of 1,654 participants aged 20-74 years looked at sleep and its effects on those with various illnesses. It followed these participants for 20 years (2). The results indicated that participants with existing high blood pressure or impaired blood sugars, who slept less than 6 hours per night, were 1.8 times likely to die of heart disease or stroke.

3. Maintain Healthy Relationships

God has created us for relationships, and they are important for overall health and healthy immune function.

Positive relationships can improve your mood and decrease stress. This, in turn, can promote a strong immune system (see more below).

To maintain relationships even when you can’t always be with each other in-person:

1. Invest in the relationships within your household and neighborhoods. Find new games to play, movies to watch, routes to walk, and other ways to make great memories together.
2. Stay in touch with loved ones however you can. Use technology to video-call, send videos to friends, and keep in touch. Social media can be a negative addiction if left unchecked, but it can also be a great way to feel a sense of community if you’re away from loved ones.

Maintain the relationships that are important to you. It’s good for your health and immune function!

4. Let Gratitude and Optimism Prevail

It’s always the perfect time to allow gratitude and optimism to prevail. You can get your gratitude journal going again. You may have started one during the Thanksgiving and the Holiday Season last year. Or, this idea may be new to you.

Gratitude journals, focusing on small daily blessings, are powerful. Being grateful is associated with better mental, emotional, and physical health and immunity.

To start a gratitude journal, first simply get a pen and a paper, or a journal. Next, write 5-10 “gratitudes” per day. They can be big or small things. You can write them throughout the day, or at the beginning or end. Just choose to focus on simple gratitudes each day as one of your lifestyle habits to support healthy immune function and more.

5. Exercise Every Day

Right now, you might feel like you don’t have many options for exercise. But actually, you have 2 great options: exercise in your home OR outside.

In fact, if you look online for free yoga, aerobic, or other classes, you’ll likely find some great ones. Some gyms and studios are offering online class streams.

Or, get outside! Whether it’s just a short walk or a ride on a bike, God has given us a huge gift in the mood-elevating outdoors. Not only is any activity good for our muscles, hearts, and brains, outdoor-activity specifically has been shown to improve mood and depression (3). What’s more, if the sun is shining, your body will make Vitamin D, an immune-stimulated vitamin.

And there’s even more good news: When you exercise, a group of immune cells called myokines are produced and released by the skeletal muscles. These promote immune function and whole-body health benefits (4).

6. Pray Continually

Prayer is not a last-ditch effort for health and immune function, but a foundation for your relationship with God, your mental health, physical health, and entire well-being.

In fact, prayer releases control from you and gives it to God. It helps change your heart towards any stressful situation, even if the situation itself doesn’t change. And lastly, it allows you to focus on truth. God’s truth is that He is with you in any circumstance. That nothing is too big. And, that He will walk with you through it.

The act of prayer has shown to increase certain helpful neurotransmitters, such as dopamine, which help promote a state of relaxation, focus, motivation, and well-being.

God has given us prayer as an amazing cortisol-releasing activity that brings us closer to Him while improving our health. As stress goes down, the efficacy of the immune system increases.

The post 8 Easy Lifestyle Habits for Healthy Immune Function appeared first on Dr. Don Colbert, MD.

In fact, it’s estimated that 25-50% of adults in the United States are deficient in Vitamin D (1).

And, it seems to be more problematic in wintertime months, when we come down with more colds and flu.

What’s the Vitamin D and immune function connection?

Here’s all about Vitamin D, the research regarding immunity, risk factors for deficiency, and how to get enough.

What is Vitamin D?

Vitamin D is a fat-soluble hormone that is both synthesized naturally by the body, and absorbed in the digestive tract.

There are two forms of Vitamin D, animal-synthesized D3 (cholecalciferol) and plant-synthesized D2 (ergocalciferol).

While humans can make the active form of Vitamin D, calcitriol, from D2 or D3, the latter is considered more effective at increasing levels.

The Science: Vitamin D and Immune Function

Vitamin D directly supports the immune system (2). It’s been shown to:

• Increases the production of disease-fighting cytokines
• Amplifies the recognition of viruses and bacteria
• Improves the body’s anti-microbial activity
• Supports the disruption of bacterial membranes and virus replication

There’s been mixed results on Vitamin D levels and specific disease outcomes. For example:

• A 2007 study showed the rate of winter-time colds and flu symptoms was reduced by more than 300% when participants supplemented with 2000 IU Vitamin D3 per day. However, the quality of the questionnaire used to gather data has come into question (3).
• In 2010, researchers found an inverse association between total Vitamin D levels and recent upper respiratory tract infections (URTI). Vitamin D levels <30 ng/mL were associated with more recent URTI than those higher (4).
• Also in 2010, scientists reported an approximate 8% reduction of seasonal influenza A in schoolchildren with Vitamin D supplementation of 1200 IU per day (5).
• Most recently, a 2017 analysis of 11,321 participants in the British Medical Journal found that those with Vitamin D levels of <10 ng/mL had a higher risk of respiratory infections compared to those at 10 ng/mL or greater (6).

There have also been studies that don’t show significant correlations. So, how much is enough?

History of Vitamin D Levels and Deficiency

There’s been controversy on what constitutes Vitamin D deficiency through the years.

Historically, any level less than 10 ng/mL was deficient.

In 2011, the Endocrine Society issued a report encouraging a higher minimum blood level of 30 ng/mL based on their research (7).

Then, the America Heart Association encouraged higher levels. It cited data that showed Vitamin D’s correlation with less degenerative disease including heart failure, depression, coronary artery disease, hypertension, and kidney failure. However, it discouraged levels greater than 100 ng/mL since these were linked to arterial fibrillation.

More studies piled up that connected Vitamin D to bone health, muscle strength and less fat accumulation, athletic performance, blood sugars, mental health, and reduced risk of some cancers.

At present, there is still no exact optimal number. However, many experts recommend 40-60 ng/mL, a possible immune- and health-enhancing range.

To get there, you may need to both avoid any risk factors you can for deficiency and proactively increase Vitamin D intake.

Risk Factors for Vitamin D Deficiency

Factors that increase the risk of Vitamin D deficiency include:

1. Lack of direct sunlight exposure in winter months. Even though you are in the sunshine in the winter, the axis of the Earth reduces the number of UV rays that directly hit us.
2. Life indoors. Compared to generations before us who mostly worked outside, modern adults now largely live indoors.
3. Limited natural food sources of Vitamin D and pollution. There simply aren’t many great natural sources of Vitamin D in our food supply. Additionally, ocean pollutions threaten the fish that do supply it.
4. Dark-pigmented skin cells. If you have darker skin, the amount of melanin in it reduces its ability to make Vitamin D from sunlight.
5. Age. As you age, your kidneys cannot convert as much Vitamin D to its active form.
6. Digestive health. If you suffer from Crohn’s disease, cystic fibrosis, and celiac disease, you may not absorb as much Vitamin D.
7. Obesity. Obesity in adults is correlated to significantly lower levels of Vitamin D.
8. Sunscreen Use. While sunscreen is very important, its use decreases Vitamin D production by the skin.

Are You Deficient? A Look at Your Numbers

If you are at risk of Vitamin D deficiency, it may be worthwhile to get your levels tested.

The most accurate measurement is the 25-hydroxy vitamin D blood test. While there are different target levels among professionals, consider a goal of 40-60 ng/mL with your doctor (8).

How to Increase Low Vitamin D Levels

If you have insufficient Vitamin D levels, you can increase them by:

• Getting outside for direct sunlight exposure to start. Try exposing skin for just 10-15 minutes per day.
• Eating wild fish such as herring, wild salmon (try this Keto Zone chowder recipe), and tuna. Cage-free eggs and cheese also supply small amounts.
• If overweight, using Keto Zone guidelines to lose weight.
• Supplementing Vitamin D3 as needed. Just 1000-2000 IU per day in the winter can raise insufficient levels, and up to 4000 IU per day can be used to correct a deficiency. Retest to monitor.

Bottom Line

Vitamin D levels decrease during the winter months and may be linked to more respiratory infections and illness. Do what you can to avoid deficiency risk factors, increase your intake as needed, and optimize your Vitamin D and immune function connection.

The post Vitamin D and Immune Function: Your Winter Guide appeared first on Dr. Don Colbert, MD.