DEAR DR. ROACH >> I read your recent article about migraines. I’m a millennial who started getting brutal migraines beginning in 2001. I saw several neurologists and took different medications, but nothing really helped.

In 2011, I started taking fish oil with high DHA daily. Since then, my migraines have dropped 95% overall, and it helps lower my migraine pain. It’s been a miracle. I’ve been preaching this for years to whomever will listen, hoping to help. There is also a DHA substitute for vegans.

— B.W.

Dear b.w. >> I’m glad the fish oil supplements have helped you and appreciate your writing to try to help.

There are not strong studies to support fish oil supplements to prevent migraines. Migraine treatments are divided into those that stop migraines, called abortive, and those that prevent migraines, called preventive. You are describing preventive treatment, and I couldn’t find anything to suggest fish oil as an abortive treatment for migraines.

However, there is a well-done study that showed a diet high in omega 3 reduced about half the number of days with migraines and the hours of migraines, but the study was unable to show an improvement in quality of life measurements. The study recommended 1.5 grams of combined n-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in roughly 1 serving per day, but the study did not look at the plant-based alpha-linolenic acid, a different type of omega 3 oil.

Your experience goes to show that perhaps supplements may be beneficial, and in any given intervention, some people get more benefit than others. Although most people will not be able to describe the dietary change as a miracle, there may be other benefits from a diet with fatty fish. Further, compared with the medications often used to reduce migraines, this diet has very few side effects.

DEAR DR. ROACH >> In various other countries, diosmin is available as a prescription medication for treating varicose veins, hemorrhoids and lymphedema. In the U.S., hesperidia and diosmin only appear to be available as supplements from companies with uncertain reputations.

Is there some way to determine the efficacy, purity and safety of these compounds available here?

— D.P.

Dear d.p. >> Diosmin is a type of flavonoid coming mostly from citrus peel that is sold in the U.S. as a medical food by prescription. There is some evidence that it is effective for varicose veins, but poor evidence that is effective for hemorrhoids. It is generally regarded as safe, with very low risk of serious toxicity, but as many as 10% of people who take it will note side effects, such as an upset stomach or skin rash. It costs about $50 per month in the U.S., according to the manufacturer’s website.

I have little experience with it, but my colleagues in wound care and vascular surgery note only modest effectiveness. One colleague compared a varicose vein to a balloon that has been over-inflated; it never returns to its normal shape, and supplements are not likely to be effective against really serious cases of varicose veins. Vascular surgeons have many tools to use in people with symptomatic varicose veins (or even for people who are concerned by their appearance).

Contact Dr. Roach at ToYourGoodHealth@med.cornell.edu.