Relating dietary fats to heart health
The new study used data that had been gathered over decades for the Glostrup Population Studies, a series of studies done in Denmark that aimed to identify relationships between environmental factors and heart disease. All of the 3,277 participants were healthy adults upon entry. They answered diet, lifestyle, and health questionnaires, had a baseline health exam, and were followed for an average of 23 years.
Throughout the follow-up period, participants were monitored for ischemic heart disease, a condition in which blood flow to the heart muscle is compromised, usually due to coronary artery disease. When all of the data was analyzed, researchers observed:
- There was no association between ALA intake and ischemic heart disease risk in women.
- A lower risk was seen in women with high intake of fish fats compared with women whose fish fat intake was low.
- No links were seen between ischemic heart disease risk and intake of the omega-6 fat known as linoleic acid, which is abundantly found in nuts, seeds, and liquid oils.
Higher intakes of ALA and fish fats were each associated with reduced risk in men (those with the highest intakes of both ALA and fish fats had the lowest risk), but neither of these relationships reached statistical significance.
Don’t forget the fish
People who have factored flaxseed and ALA into their diets need not abandon their favorite products. Although they may not prevent ischemic heart disease, flaxseeds may have other benefits, such as diabetes prevention and alleviation of menopausal symptoms. But for wider protection, it makes sense for now to eat fish a few times per week or take a fish oil supplement.
The rest of your fat intake should supply a balance of fatty acids:
- Omega-3. Flaxseeds are the richest source of ALA. Other foods with high ALA content include walnuts, soy oil, and meats from grass-fed animals.
- Omega-6. The major omega-6 fats are linoleic acid from nuts, seeds, and vegetable and seed oils, and arachidonic acid from peanuts, meat, eggs, and dairy products. These fats are essential for good health, but many nutrition experts believe that maintaining a balance between omega-6 and omega-3 fats is the key. Most recommend that our omega-6 fat intake should be two to four times higher than out omeg-3 fat intake; unfortunately, most of us get far more omega-6 fat than we need, and most of it is the less healthy arachidonic acid.
- Omega-9. Oleic acid is an omega-9 fat from olives, olive oil, macadamias, and other nuts. Although the body can make oleic acid from omega-3 and omega-6 fats, studies have found that high dietary intake of oleic acid is good for the heart.
(Am J Clin Nutr 2011;doi: 10.3945/ajcn.111.018762)