Dairy Trans Fats and Your Heart: What 22 Studies Really Found

Picture yourself at the grocery store, holding a block of good aged cheese. You flip it over, see a small amount of trans fat on the nutrition panel, and hesitate. After all, we have spent decades hearing that trans fat is one of the worst things you can put in your body.

So here is a fair question many of my patients ask: are dairy trans fats, the kind that form naturally in milk, butter, yogurt and cheese, just as harmful as the factory-made trans fats in fried and processed foods? A major new review of 22 studies suggests the answer may be no.

As ScienceDaily reported under the headline “Not all trans fats are bad, major review finds,” researchers found no signs that the natural trans fats in dairy raised the risk of heart disease, stroke or type 2 diabetes. But there is an important part of this story that the headline leaves out, and I want you to hear the whole thing.

The study was paid for by the dairy industry. That does not automatically make it wrong, but it does mean we read it with wisdom. Let me walk you through what was found, what it means, and what I would actually do with this information at your kitchen table.

🔬 What the New Dairy Trans Fats Study Found

The research, published in the journal Nutrition Research in 2026, was led by scientists connected with the University of Reading in England. It is a systematic review and meta-analysis. That simply means the researchers searched the medical literature in a careful, organized way, gathered the relevant studies, and in some cases pooled the numbers together to look for a clearer overall answer.

They looked at two kinds of human research, drawing on thousands of participants in Europe, Canada and the United States.

Part one: 10 controlled feeding trials

In these 10 randomized controlled trials, one group of people ate dairy foods that had been specially produced to contain higher levels of natural trans fat. The other group ate regular dairy. According to the University of Reading press release, trans fat intakes ranged from 1.3 to 13.2 grams per day.

When the researchers pooled the results, there were no significant differences in blood fat markers, including total cholesterol, LDL cholesterol, triglycerides and ApoB (a protein that carries cholesterol particles through the blood). There was one exception. HDL cholesterol, often called the “good” cholesterol, dipped slightly in the enriched dairy groups, by an average of 0.05 mmol/L, according to the published abstract. That is a small change, but it is a real finding and I don’t want to brush past it.

Part two: 12 long-term population studies

The second part reviewed 12 prospective cohort studies. These follow large groups of people over many years, in some cases more than 20, and track who develops health problems. Here the researchers looked at blood levels of two natural dairy trans fats called trans vaccenic acid and trans palmitoleic acid.

People with higher blood levels of these dairy trans fats did not have a higher risk of heart disease, stroke or cardiovascular death. They also did not have a higher risk of type 2 diabetes.

The honest limitations

Now let me put on my physician’s reading glasses. Here is what you should know before anyone tells you this study “proves” anything:

• Industry funding. The University of Reading states that the research was funded by the National Dairy Council (USA), and that several authors work for or receive funding from dairy industry organizations.
• An independent voice raised a flag. Nutrition professor Marion Nestle highlighted it on her Food Politics blog as an “industry-funded study of the week” and said she would like to see independent scientists test the same question.
• The hypothesis was stated up front. The authors expected to find no effect, which is worth keeping in mind.
• Modified dairy in the trials. The feeding trials used dairy with naturally enhanced trans fat levels, not ordinary supermarket products.
• Association, not cause. The cohort studies measured blood markers. They can show a link (or the lack of one), but not proof of cause and effect.
• A narrow question. The study did not test saturated fat or overall dairy intake, so it does not show that butter or cheese is heart-protective.
• A correction was published. A corrigendum to the paper appeared in Nutrition Research in August 2026. I have not been able to review it, so I am sticking to what the abstract and press release report.

One study, even a review of 22 studies, is never the final word. But it does add an important piece to a conversation many of us have misunderstood for years.

🧈 Natural vs Artificial Trans Fats: Why They Are Not the Same

“Trans fat” is not one single thing. It is a family of fats with a particular chemical shape. Where that fat comes from, and which members of the family you are eating, appears to make a big difference.

Industrial trans fats: still the real villain

Industrial trans fats are made in factories through a process called partial hydrogenation, which turns liquid vegetable oil into a more solid fat that keeps well on a shelf. For years these partially hydrogenated oils showed up in some fried foods, baked goods and packaged snacks.

The World Health Organization is clear: industrially produced trans fats have no known health benefits, and intake above 1 percent of total energy is linked to a higher risk of coronary heart disease events and death. That is why WHO has worked to eliminate them from the food supply. Nothing in this new review challenges that, and the authors themselves stress the point.

Natural dairy trans fats: a different story

Trans fats also occur naturally, at lower levels, in meat and dairy from ruminants, the cud-chewing animals such as cattle, sheep, goats and camels. WHO acknowledges this as well. The lead author of the new review emphasized that these dairy trans fats are not the same as industrial partially hydrogenated fats.

Here is an interesting twist. The study abstract notes that as industrial trans fats are removed from our food, dairy is becoming a major dietary source of the trans fat people still eat. That is exactly why this question matters now. If you see trans fat on the label of your yogurt or cheese, it is most likely the natural kind.

❤️ Is Butter Bad for Your Heart? Full-Fat Dairy and Heart Health

This is where I want to be very careful, because headlines love to jump from “not all trans fats are bad” to “butter is health food.” That is not what this study showed.

Dairy fat is still mostly saturated fat. Mayo Clinic Press notes that dairy saturated fat can raise LDL cholesterol. At the same time, it reports that recent research suggests milk, cheese and yogurt are not directly associated with a higher risk of heart disease or stroke. In one large French cohort, full-fat dairy was not linked to heart disease or stroke, and fermented full-fat cheese and yogurt were linked to a lower stroke risk.

Harvard Health Publishing adds an important balance. In pooled Harvard cohort data, dairy fat was not associated with higher cardiovascular risk compared with the same calories from carbohydrates. But replacing about 5 percent of calories from dairy fat with unsaturated fat from vegetables or vegetable oils was linked to a 24 percent lower risk. Harvard’s conclusion is that plant-based fats are probably a better choice than cheese.

Meanwhile, the American Heart Association still recommends that adults and children age 2 and older choose milk and milk products low in dairy fat. Mainstream guidance has not changed because of this review.

So what do I tell my patients? In my practice, I often see people who have been taught to fear a spoonful of real butter while they eat packaged snack foods without a second thought. That is backward. The bigger problem is usually ultra-processed, fried and packaged foods. Real dairy, if you tolerate it, can have a place in a whole-food diet, in moderation, alongside plenty of healthy plant fats such as olive oil, avocados and nuts. I explain more about these in my article on 7 healthy fats.

🥗 Practical Steps: Eating Wisely After This Headline

Here is how I would turn this research into simple, sensible choices this week. None of these steps is meant to replace your doctor’s advice, especially if you have a heart condition or high cholesterol.

If you would like to understand your own heart risk more clearly, I have written about the coronary artery calcium score, one of the tests I find helpful when patients want a clearer picture than a cholesterol number alone can give.

And if you have heart disease, high LDL cholesterol or familial hypercholesterolemia (an inherited form of very high cholesterol), take cholesterol medicine, or have lactose intolerance or a dairy allergy, please talk with your doctor before changing how much dairy you eat.

📋 Your Action Plan on Dairy Trans Fats

1. Separate the two kinds of trans fat in your mind. Industrial trans fats from partially hydrogenated oils remain harmful. The natural dairy trans fats in this review were not linked to heart or diabetes risk.
2. Check your pantry this week. Look at ingredient lists on crackers, cookies, frozen foods and coffee creamers. Anything with partially hydrogenated oil goes.
3. Choose real dairy over processed imitations, if you tolerate it. Plain yogurt and real cheese are closer to how God made them than many highly processed spreads and snack products.
4. Keep portions sensible. Dairy fat is still mostly saturated fat, which can raise LDL. Enjoy it as part of a meal, not as the meal.
5. Make plant fats your foundation. Use extra virgin olive oil for cooking and dressings, and add avocados, walnuts or almonds to your day.
6. Get your labs and talk with your doctor. Bring this article to your next visit and ask how dairy fits your personal cholesterol numbers and heart history. Do not change any medication on your own.
7. Practice wise headline reading. Every time you see a nutrition headline, ask whether it was in people, who funded it, and what it actually tested.
8. Give thanks for your food. Pause before meals to thank God. Gratitude slows us down, and slower eating tends to be wiser eating.

❓ Frequently Asked Questions

Are dairy trans fats bad for you?

In this new review of 22 human studies, natural dairy trans fats were not linked to higher risk of heart disease, stroke, cardiovascular death or type 2 diabetes, though the trials showed a small dip in HDL cholesterol. The study was funded by the dairy industry, so independent confirmation would be valuable. It is reassuring, but not the final word.

What is the difference between natural and artificial trans fats?

Artificial, or industrial, trans fats are made in factories by partially hydrogenating vegetable oils, and WHO says they have no known health benefits. Natural trans fats form at lower levels in meat and dairy from cud-chewing animals such as cows, sheep and goats. The researchers emphasize that the two should not be treated as the same.

Is butter bad for your heart?

This study did not test butter or saturated fat directly, so it cannot answer that fully. Dairy fat is mostly saturated fat, which can raise LDL cholesterol, and Harvard data suggest plant fats are probably a better everyday choice. Butter in modest amounts as part of a whole-food diet is very different from a diet full of fried and packaged foods, but ask your doctor what is right for your numbers.

Should I switch to full-fat dairy?

Not based on this study alone. The American Heart Association still recommends low-fat dairy, and some research on full-fat and fermented dairy is encouraging but mostly observational. If you have high LDL, heart disease or take cholesterol medicine, talk with your physician before making the switch.

Does industry funding mean a study is wrong?

No, but it is a good reason to read carefully and look for independent research on the same question. Funding can shape which questions get asked and how results are presented. Wise readers note the funding, look at the study design and limitations, and wait for confirmation.

🙏 A Final Word

For years, the word “trans fat” has carried a heavy cloud of fear. This new review suggests that the small amounts of natural trans fat in milk, yogurt, butter and cheese may not deserve that same cloud, while the factory-made kind still does.

But the bigger lesson is not about one fat. It is about wisdom. God gave us real food to enjoy with thanksgiving, and He gave us minds to test what we hear. Choose foods closer to how He made them, keep your portions sensible, lean on healthy plant fats, and work with your doctor on your personal numbers. That is stewardship, and it leads to peace instead of fear.

You do not have to figure it all out at once. Take one step this week, perhaps clearing out a few packaged foods with partially hydrogenated oils, and trust God to guide the next one.

Dr. Don Colbert, MD