Research Round Up: Health Benefits of Full Fat Dairy

Fellow of the Academy of Nutrition and Dietetics Leigh-Anne Wooten, MS, RDN/LDN, FAND, provides a round-up of research on full fat dairy.

Dairy products including milk, yogurt, cheese, and kefir are incredibly nutrient dense, providing a wide array of essential vitamins (A, B6, B12, D and K), minerals (calcium, iodine, magnesium, potassium, phosphorus and zinc), probiotics (in fermented dairy), fat, and protein.  A number of these nutrients are otherwise quite difficult to get enough of through the average American diet.

For decades the recommendations from researchers, physicians, and government dietary guidelines have all focused on encouraging consumption of specifically low or nonfat dairy, some going so far as to outright advise against eating full fat dairy.  Historically, the assumption was made that full fat dairy could contribute to elevated cholesterol and weight gain, and negatively impact overall cardiovascular health due to its saturated fat and cholesterol content. However, the most current research paints a very different picture suggesting that full fat dairy can have a very positive effect on health when eaten in moderation.  And the evidence is very compelling.

Cardiovascular Health
There are two nutrients in full fat dairy that usually get the blame for wreaking havoc on the body, saturated fat and cholesterol.  Let’s go to the research to see what it says.  And remember, when we’re looking at research, we want to draw conclusions based on the highest quality studies out there, which are meta analyses and systematic reviews of randomized controlled trails.  While animal studies and observational research also help the scientific community, it’s these larger reviews that provide enough evidence to make sweeping recommendations to entire populations.

In this literature review, Dairy Fats and Cardiovascular Disease, Do We Really Need to Be Concerned? the authors conclude that the latest studies have effectively squashed the old school notion that the fat in dairy is bad, and successfully demonstrated the benefits of full fat dairy consumption on cardiovascular health.  And perhaps the most powerful study is this overview of systematic reviews and meta-analyses that compiled and interpreted all existing data on the topic.  And the verdict? The consumption of dairy products, no matter what kind, does not increase the risk for cardiovascular disease.  They actually found a decreased risk with dairy consumption. 

What about the cholesterol in full fat dairy; can it increase the levels of cholesterol in the blood? The research around this has evolved as well.  Where we once thought that dietary cholesterol was the main contributor to blood cholesterol, newer evidence points to genetics and other factors as the leading causes.  As it relates specifically to dairy, studies have demonstrated that full fat milk does not negatively affect blood lipid levels and in fact can increase good cholesterol (high density lipoprotein, HDL).  The body of evidence is so strong that interestingly, a number of countries around the world don’t even have a recommended upper limit for dietary cholesterol.

Weight Management
A healthy weight is one strong indicator of cardiovascular and overall health.  Many people looking to lose weight avoid full fat dairy among other foods because of the extra calories; however, studies show that consuming this extra fat might in fact help support weight management.  How? While the root cause is still being determined, many researchers point to the ‘satiety factor’ as one likely explanation.  We know that foods containing fat, fiber, and/or protein actually slow down digestion and absorption, making us feel fuller faster and for longer periods of time. As a result, some people end up eating less. 

According to this study of over 18,000 women, greater intake of high-fat dairy products, but not low-fat, was associated with less weight gain. And this systematic review concluded that the abundance of data does not support the theory that high-fat dairy foods contribute to obesity. It goes on to say that moderate consumption of high fat dairy decreases risk for obesity.  And finally, this meta-analysis (reviewing 37 randomized controlled trials) showed that when participants restricted total calories but included high fat dairy as a part of their daily intake, they lost both weight and body fat, suggesting that full fat dairy helps preserve muscle. 

I think the evidence is speaking, quite loudly, for itself.

So, Why All the Confusion?
First it must be said that high quality nutrition research is inherently difficult to conduct. The level of reliable data needed to make sweeping recommendations for entire populations takes decades of work. And of course, there are ethics involved. We can’t make people eat a certain diet and account for every single confounding factor for their entire life which is required to truly see how one variable impacts another.

Also, nutrition research has traditionally followed a ‘nutrient-focused’ approach, evaluating the effect of a single nutrient group on one health effect.  For example, in 1980, the first U.S. Dietary Guidelines were released and recommended low fat or fat free dairy (which remains today).  These recommendations were based on the theory that if saturated fat (one single nutrient group) is bad for cardiovascular health (one health effect, ALL foods with saturated fat, including dairy, should be avoided.

Once scientists zoomed in and started looking specifically at full fat dairy and not just saturated fat, a new theory started to unravel.  In this scientific review researchers concluded that the evidence to date does not support the current recommendations to only eat low fat or fat free dairy to reap its wide array of health benefits.  It further noted that dairy is a nutrient dense food source that can be eaten in moderation and full fat dairy can be supportive of cardiovascular health.

How Full Fat Dairy Works to Support Cardiovascular Health
This is a hot topic in the scientific community right now. A lot of researchers are digging into this very question and there are several interesting observations.

- Not all saturated fats are made equal.  There are actually many different kinds of saturated fats, some that may harm the cardiovascular system and some, that we are now finding, can be cardioprotective, like the ones found in full fat dairy.

- Full fat dairy increases the bioavailability of certain nutrients, specifically the fat-soluble vitamins A, D, E, and K.  These vitamins which are important to cardiovascular health, require fat in order to be absorbed into the body to do their jobs.  Dietary fat, like what is found in full fat dairy, acts like a car carrying the vitamins through the GI tract, into the blood, and to the liver where they are stored until the body needs them.  If you don’t have fat, your body can’t capture and store those fat-soluble vitamins.

- Full fat dairy may have anti-inflammatory properties that support long term cardiovascular and overall health.

- And of course, there may be interactions between nutrients that science has not yet been able to identify.

Current Recommendation
Based on the evidence we have to date; it’s safe to say that the majority of people will benefit from full fat dairy in moderate amounts as a part of a healthy and balanced lifestyle. (Individuals who already have high cholesterol and/or cardiovascular disease should talk with their doctor or registered dietitian when making dietary choices.) 

Importantly, when it comes to children, the guidance from the medical community is to provide full fat milk between 12-24 months to reap the benefits from DHA and EPA, two essential fats (meaning your body can’t make them on its own) found in abundance in full fat milk.  DHA and EPA are critical in young children for brain development.   While the current recommendation is to switch to a lower fat milk after two years of age, experts say this is not backed up by evidence.

Contrary to popular belief, research shows that full fat dairy is not associated with an increased risk of obesity in children.  Just remember the recommended amount of dairy after age two is 16 ounces per day.  More than that can inhibit the absorption of iron in children (and adults), may replace other nutrient dense foods and can lead to lack of energy and growth concerns.

No one will deny that full fat dairy is delicious.  It’s also easily accessible and the best bang for your buck to get the essential nutrients commonly lacking in the American diet.  So, drink up!