DEAR DR. ROACH: I have a question about consuming omega-3 fatty acids, either through fish consumption or by dietary supplements like fish oil. Apparently, many American diets lack omega-3 fatty acids. One possible reason is that most American beef cattle are fed primarily corn rather than their natural diet of grass, leading to meat that is low in omega-3. Most arguments for increasing the content of omega-3 fatty acids seem to be related to heart health. But omega-3 fatty acids are also important for brain health. I specifically wonder if there might be a link between these diet-induced low omega-3 levels and our epidemic of dementia and Alzheimer̵
ANSWER: Grass-fed beef has more omega-3 oils than grain-fed beef. However, the amount, even in grass-fed beef, is still quite small compared to other sources. A standard serving of grass-fed top tenderloin beef has approx. 65 mg omega-3 fats, approx. 50% more than grain-fed. There is no “officially” recommended intake level for omega-3 fatty acids, but the Institute of Medicine noted that healthy adults consume 1,100 (women) and 1,600 (men) a day.
Grass-fed beef is not really a good source to get there. It would take 4.5 kilos of grass-fed beef daily to reach the goal for men – not a healthy choice. A single serving of salmon has more than 1,800 mg. More importantly, although the data remains mixed, most studies show that changing a diet from red meat-based to plant- and fish-based leads to a reduced risk of heart disease and stroke.
Studies in populations have shown that a 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 trials using omega-3 supplements for the treatment or prevention of dementia, such as Alzheimer’s, have shown no benefit or at most a small benefit.
In my opinion, a diet 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 like eating beef, I recommend that you only do it occasionally. Until there are clear benefits that show that grass-fed beef has health benefits compared to grain-fed, I think it is far more important to eat sparingly with beef than to switch to the grass-fed.
DEAR DR. ROACH: I am an honest 92 year old woman. I eat a lot of vegetables, fruits and seafood. My doctor said a 20 year old would be jealous of my blood work. I train four days a week with slow jogging, stretching and weight lifting.
My problem is that my blood pressure is usually around 135/70, sometimes a little higher or lower. I’m worried it’s too high, but my doctor is happy with this figure. What is your opinion? – RY
REPLY: A score of 135/70 in a healthy person without other risk factors is usually not an indication for drug treatment. But just being 92 years old is a risk for heart disease and it is a good idea to try to reduce the risk where you can. It seems that you have done remarkably well with your diet and exercise, and it probably helps your blood pressure as well.
I agree with your doctor that your blood pressure does not need treatment beyond the healthy lifestyle you have chosen, but your desires matter. If you really want to treat it, I would consider an extremely low dose of one of the safest blood pressure medications. Any benefit of medication would be small.
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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them into the column whenever possible. Readers can send questions to ToYourGoodHealth@med.cornell.edu or email 628 Virginia Dr., Orlando, FL 32803.
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