This has been the conclusion made from a number of large and small studies over the past two decades by different researchers around the world.
But now we have an even more clear conclusion from a study that focused specifically upon the relative consumption of different fats. In particular, both dairy and animal fats versus plant-based fats.
What is different about this study?
Many studies have focused upon the larger magnitude of the diet. They have addressed the total diet, or the relative consumption of animal-based foods or plant-based foods. Yes, some have focused upon types of fats, such as saturated fats. But most have focused intently upon the relative consumption of different types of fats.
In addition, none have included and stratified diary fats from the rest of animal fats. And separated polyunsaturated fats from the rest of plant-based fats.
Furthermore, this study didn’t just compare diets, it also compared replacing one type of fat for another.
Plus, this is an incredibly large study done by distinguished researchers from Harvard University.
Dairy fat compared
The research comes from the Harvard School of Public Health. The study followed 43,652 men for 24 years, 87,907 women for 32 years, and another 90,675 women for 20 years. The scientists assessed the relative diets among the subjects every four years.
During the duration of the research, there were 14,815 cases of cardiovascular disease among the subjects. This included 8,974 cases of coronary heart disease and 5,841 cases of stroke.
The researchers calculated that when dairy fats are replaced with the same calories from plant-based fats, the risk of cardiovascular disease dropped by 10% percent.
But more profound was the result that replacing dairy fats with polyunsaturated plant-based fats decreased the risk of cardiovascular disease by almost a quarter – by 24 percent.
Dr. Frank Hu – a Harvard professor and lead author of the study said:
“These results suggest that dairy fat is not an optimal type of fat in our diets. Although one can enjoy moderate amounts of full-fat dairy such as cheese, a healthy diet pattern tends to be plant-based and low in saturated fat.”
What if dairy is replaced by whole grains?
This result was also profound. Replacing dairy fat with carbohydrates from whole grains reduces cardiovascular disease risk by a whopping 28 percent.
The key to this is whole grains, however. When dairy fat was compared to carbohydrates from refined foods, there was little difference in risk.
What about other animal fats?
Using the same tools and study population, the researchers also calculated the CVD risk of replacing dairy fat with other animal fats. This included red meats. The research found that the risk of cardiovascular disease increased by six percent when dairy fat was replaced by animal fats.
Okay, so let’s do the math. If dairy fats increase the risk of cardiovascular disease over polyunsaturated fats by 24 percent, this means animal fats increase CVD risk by 30 percent.
And animal fats increase CVD risk by 34 percent compared to carbohydrates from whole grains.
Practical diet planning
These calculations were made with practical diet planning in mind. The concept is that not only do we have grand choices of diet. We also have day-to-day choices relating to which type of fats we choose.
And since fats are only a portion of our diet, and our choices are often limited, this research reflects our choices.
This also points to the relative risks of heart disease as we select our cooking fats. Should we cook that food in butter? Or should we cook it in a plant-based vegetable oil?
Some studies have bashed polyunsaturated fats. Others have questioned the multitude of studies showing that increased saturated fat consumption (over a healthy level) increases the risk of heart disease.
But we must remember that this study was incredibly long. It creates a dimension of accuracy that negates many short-term studies.
That said, the majority of research still concludes that a diet with high levels of plant-based fats reduces the risk of heart disease. And even when there is some heart disease, those who eat more plant-based polyunsaturated fats have better outcomes.
This was found in another recent study – from the National Cerebral and Cardiovascular Center in Osaka, Japan. The study tested 751 people who checked into the hospital with heart disease. The research followed the patients for 560 days.
The research determined that having higher levels of polyunsaturated fats in the bloodstream was associated with better clinical outcomes.
Regarding the study from the Harvard School of Public Health – the source of some of the most distinguished unbiased diet research throughout the world – Dr. Hu added:
“These results strongly support existing recommendations to choose mainly unsaturated fats from vegetable oils, nuts, seeds, avocados, and some oily fish for a heart-healthy diet.”
What about low-fat dairy?
Not sure it makes much of a difference. A twelve-week study from the University of Copenhagen followed 139 people for 12 weeks. The research found there was little difference in cholesterol or other metabolic syndrome markers between those who ate low-fat cheese and full-fat cheese.
However, this study confirms the big one from Harvard. Those who didn’t eat cheese during the 12 weeks had higher HDL-cholesterol. This is the “good” cholesterol because it produces less oxidative radicals.
REFERENCES:
Chen M, Li Y, Sun Q, Pan A, Manson JE, Rexrode KM, Willett WC, Rimm EB, Hu FB. Dairy fat and risk of cardiovascular disease in 3 cohorts of US adults. Am J Clin Nutr. 2016 Nov;104(5):1209-1217.
Nagai T, Honda Y, Sugano Y, Nishimura K, Nakai M, Honda S, Iwakami N, Okada A, Asaumi Y, Aiba T, Noguchi T, Kusano K, Ogawa H, Yasuda S, Anzai T; NaDEF investigators.. Circulating Omega-6, But Not Omega-3 Polyunsaturated Fatty Acids, Are Associated with Clinical Outcomes in Patients with Acute Decompensated Heart Failure. PLoS One. 2016 Nov 8;11(11):e0165841. doi: 10.1371/journal.pone.0165841.
Adams C. The Ancestors Diet: Living and Cultured Foods to Extend Life, Prevent Disease and Lose Weight. Logical Books, 2015.