pouring milk into a glassWe are all aware of the current obesity trend in this country and across the globe.  Avoiding fat in our diet has been the conventional mantra now for the last 4 or 5 decades.  But what has this low-fat obsession gotten us?  Well, Americans are now fatter than ever.  Paralleling that trend has been a dramatic rise in diabetes cases and, cardiovascular disease remains the number one killer of Americans.  New research has focused on a trans fat component found mainly in dairy fat that may ward off type 2 diabetes and protect cardiovascular health. While more research is needed, it suggests fats may play a more complex role in human health than previously acknowledged.

Many health and nutrition experts have long recommended limiting dietary saturated fats and avoiding full fat dairy products.  Marion Franz, a registered dietitian with the American Diabetes Association nutrition task force was quoted as saying, “the link between eating saturated fats and heart disease is well established.” Yet a recent meta-analysis failed to show any increased risk of coronary heart disease or cardiovascular disease from saturated fats.[1]  Trans fats found in hydrogenated oils are industrially produced and have been associated with higher risks from heart disease.   In contrast, researchers found that adults with the highest levels of trans-palmitoleic acid in their blood had a three-fold lower risk of developing diabetes.  Interestingly, those individuals also had lower body fat, higher good cholesterol levels, and lower triglyceride levels, which are all associated with better cardiovascular well outcomes.[2]   Trans-palmitoleic acid is a naturally occurring fatty acid found in milk, cheese, yogurt, butter and meat.

This study examined 3,736 participants in the National Heart, Lung, and Blood Institute-funded Cardiovascular Health Study, who have been followed for 20 years in an observational study to evaluate risk factors for cardiovascular diseases in older adults.  “It’s exciting because traditionally fats were just seen as artery cloggers, but they seem to be both harmful and protective,” said lead author and Harvard epidemiologist Dariush Mozaffarian. “The fatty acid world is becoming more interesting and complex.”

There are a number of problems with the current low-fat recommendations.  It has created an environment where people avoid all fats indiscriminately, when many are healthy and beneficial.  In fact, in order to burn fat you need to eat fat.  Another major problem has been the substitution of refined carbohydrates for the fats.   It is abundantly clear that excess highly processed carbohydrates leads to insulin resistance and the accumulation of excess body fat (see “Low Fat vs Low Carb”). 

Being overweight or obese is far more than just carrying around excess weight or wearing bigger clothes.  It is a well-established risk factor for diabetes, heart disease, hypertension, elevated cholesterol, stroke, metabolic syndrome, arthritis, several cancers and premature death.

We all know that adopting a healthier lifestyle can significantly reduce the epidemics of obesity and type 2 diabetes.  The same healthy lifestyle modifications can lower your risk of heart disease and certain cancers.  Should we all start drinking more milk?  No, these finding are still preliminary.  There have been several studies that suggest dairy lovers have a lower diabetes risk, but there are also many studies linking the same benefit to the Mediterranean diet — typically low in dairy, but high in fats from olive oil and fish, and rich in high-fiber grains, vegetables and legumes.  A separate meta-analysis of 17 prospective studies looking at the association between dairy consumption and cardiovascular disease concluded that milk consumption was not harmful but did not demonstrate any significant cardiovascular risk reduction.[3]

So for the meantime, it is best to maintain a healthy weight by exercising regularly and following a diet lower in refined carbohydrates, higher in protein and healthy fats than the typical American diet.  But if you enjoy milk, there is no reason to avoid it because of its fat content.

[1] Siri-Tarino PW, Sun Q, Hu FB, Krauss RM. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr 2010; 91:535-546

[2]  Mozaffarian D, Cao H, King I, Lemaitre R, Song X, Siscovick D, Hotamisligil G, ‘Trans-Palmitoleic Acid, Metabolic Risk Factors, and New-Onset Diabetes in U.S. Adults: A Cohort Study’, Ann Intern Med December 21, 2010 153:790-799

[3] Soedamah-Muthu SS, Ding EL, Al-Delaimy WK, et al. Milk and dairy consumption and incidence of cardiovascular diseases and all-cause mortality: dose-response meta-analysis of prospective cohort studies. Am J Clin Nutr 2010; DOI: 10.3945/acjn.2010.29866.