Research & Education

Dairy Fat Exonerated Again

Perhaps it’s time to put the final nail in the coffin of low-fat and fat-free dairy products once and for all. Over and over, research has refuted connections between saturated fat intake and cardiovascular disease risk. Even if mainstream nutritionists aren’t quite ready to give lard and tallow a free pass (even though these have a high percentage of monounsaturated fat in addition to their saturated component), it’s time to break dairy fat out of jail for health crimes it was accused of decades ago, but which has since been proven multiple times it didn’t actually commit.

Owing to their relatively high percentage of saturated fatty acids, and the long-held belief that saturated fat had a nefarious hand in every adverse health outcome one could imagine—obesity, type 2 diabetes, heart attack, cardiovascular disease, stroke—for decades, full-fat dairy products were practically an endangered species. It was difficult to find real butter hiding among the margarine and low-fat vegetable oil spreads. A feat to find cream-top yogurt in the sea of nonfat varieties, and a rare occurrence to find cream cheese, sour cream, and other dairy foods in their full-fat state, rather than brandishing labels proudly boasting that they’d had every possible molecule of fat removed.

Bob Dylan said it best: “the times, they are a-changin’.” Or, they should be changing, thanks to a recent study that lends even more weight to the already large body of research indicating that dairy fats have been innocent all along: “The totality of evidence does not support that dairy SFAs [saturated fatty acids] increase the risk of coronary artery disease or stroke or CVD mortality.” This quote comes from a paper titled A changing view on SFAs and dairy: from enemy to friend. It’s nice that the quote gets right to the point, but the fact is, dairy fat—and all saturated fat, really, never was the enemy.

If someone opts for low-fat or fat-free dairy products because they prefer the flavor or texture, that’s one thing, but if they’re selecting reduced fat options due to fear of saturated fat, it’s time for this myth to go the way of the oat bran craze from the 1980s. (In other words, it needs to go away and never be heard from again.)

If we wanted to create the perfect storm of adverse public health outcomes, we couldn’t have done much better than demonizing dairy fat:

“The emerging scientific evidence indicates that the consumption of regular fat dairy foods is not associated with an increased risk of cardiovascular disease and inversely associated with weight gain and the risk of obesity.” (Source)

Numerous studies corroborate the lack of association between dairy fats and cardiovascular problems. Two are fairly recent—the one mentioned above, and another from earlier this year. The one that was just published was funded by the NIH and the senior author was Dariush Mozaffarian, MD, dean of the Friedman School of Nutrition Science and Policy at Tufts University. So, this isn’t exactly some fringe group of dairy farmers trying to erase a half-century of fearmongering around saturated fats in dairy. This is as mainstream as it gets.

According to Marcia Otto, PhD, the study’s corresponding author, “In addition to not contributing to death, the results suggest that one fatty acid present in dairy may lower risk of death from cardiovascular disease, particularly from stroke.” So it’s not just that dairy fat isn’t harmful; it may actually be helpful. Hard to believe the “experts” got it wrong for so long, but it certainly wouldn’t be the first time.

The particular fat in question—the one that seems to reduce risk of death from CVD or stroke—is heptadecanoic acid, a 17-carbon saturated fatty acid. Another study found that plasma phospholipid concentration of a different fat—pentadecanoic acid (15 carbons, and used as biomarker of dairy fat consumption)—was inversely associated with CVD and coronary heart disease. These odd-chain fatty acids are found primary in ruminant animal fat, including dairy products.

The same finding—that circulating biomarkers of dairy fat consumption are not associated with stroke—were arrived at in assessing 2 large cohorts, the Health Professionals Follow-Up Study (n = 18,225) and the Nurses’ Health Study (n = 32,826). This paper includes authors from Harvard and Tufts, so again, not some dairy industry front group trying to drum up good PR.

Before we close this out, let’s slay another sacred cow…no pun intended! There’s a lot of buzz about the dangers of trans fats in the food supply. (Trans fats are formed when polyunsaturated vegetable oils, which are typically liquid at room temperature, are bombarded with hydrogen atoms, which “partially hydrogenates them” and makes them solid or semi-solid, allowing them to be used in processed foods intended to have a long shelf life.) But lest we throw the baby out with the bathwater, all trans fats are not created equal.

The trans fats created through partial hydrogenation have very different effects than the ones that occur naturally in dairy fats and other ruminant animal fats, such as tallow and suet. While a daily consumption of 5 grams of industrially produced trans fats was associated with a 29% increased risk of coronary heart disease, this association was not found in ruminant animal-derived trans fats up to a daily intake of 4 grams. (Yes, there’s a 1 gram difference there, but the researchers point out that depending on someone’s diet, it can be very easy to consume as much as 20 grams of industrial trans fats, but even with a high dairy intake, it would be nearly impossible to get that much ruminant trans fat.)

The 2015 Dietary Guidelines for Americans recommends fat-free or low-fat dairy, but if you’ve taken the time to read labels, these reduced fat products are typically loaded with sugar, particularly in the case of yogurt and flavored fat-free milks. Dr. Otto said it well: “Consistent with previous findings, our results highlight the need to revisit current dietary guidance on whole fat dairy foods…” Let’s hope the committee writing the next 5-year set of guidelines is listening.

By Amy Berger, MS, CNS