Dear Dr. Roach • I have a question about omega-3 fatty acid intake, either through fish consumption or by dietary supplements like fish oil. Apparently, many American diets are deficient in omega-3 fatty acids. One possible reason is that most American beef cattle are fed primarily on corn rather than their natural diet of grass, leading to meat that is low in omega-3. Most arguments for increasing omega-3 fatty acid intake seem to be related to cardiac health. But omega-3 fatty acids are also important for brain health. I’m wondering specifically if there might be a correlation between these dietary-induced low omega-3 levels and our epidemic of dementia and Alzheimer’s disease. — A.J.S.
Answer • Grass-fed beef has more omega-3 oils than grain-fed beef. However, the amount, even in grass-fed beef, is still fairly small compared with other sources. A standard serving of grass-fed top sirloin beef has about 65 mg of omega-3 fats, about 50% more than grain-fed.There is no “official” recommended intake level for omega-3 fatty acids, but the Institute of Medicine noted that healthy adults take in 1,100 (women) and 1,600 (men) per day.
Grass-fed beef isn’t really a good source to get there. It would take 4.5 pounds of grass-fed beef daily to achieve the goal for men — not a healthy choice. A single serving of salmon has more than 1,800 mg. More importantly, although the data remain mixed, most studies show changing a diet from red-meat-based to plant- and fish-based leads to decreased risk of heart disease and stroke.
Studies on populations have shown that high dietary intake of omega-3 fatty acids is associated with a reduced risk of developing dementia, as well as a reduction in high blood pressure and heart disease. However, clinical studies using omega-3 supplements to treat or prevent dementia such as Alzheimer’s have shown no benefit or at most a small benefit.
In my opinion, a diet that is rich in fruits and vegetables, legumes, nuts and fatty fish, such as many Mediterranean-style diets, has many health benefits, including reduced risk of dementia and vascular disease. If you do like to eat beef, I recommend doing so only occasionally. Until there are clear benefits showing grass-fed beef has health benefits compared with grain-fed, I think it’s far more important to eat beef sparingly than to change to grass fed.
Dear Dr. Roach • I am a heathy 92-year-old woman. I eat a lot of vegetables, fruit and seafood. My doctor said a 20-year-old would be envious of my bloodwork. I exercise four days a week with slow jogging, stretching and weightlifting.
My problem is that my blood pressure is usually around 135/70, sometimes slightly higher or lower. I am concerned that it is too high, but my doctor is pleased. What is your opinion? — R.Y.
Answer • A result of 135/70 in a healthy person with no other risk factors is usually not an indication for medication treatment. However, just being 92 years old is a risk for heart disease, and trying to reduce risk where you can is a good idea. You seem to have done remarkably well with your diet and exercise, and that is probably also helping your blood pressure, too.
Your blood pressure does not need treatment. If you really wanted to treat it, I would consider an extremely low dose of one of the safest blood pressure medicines. Any benefit from medication would be small.
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