Get nutrients from food, not supplements


Hello again, dear readers, and welcome to the continuation of this month’s letters column. Our volume of mail keeps growing, so we’ll be adding extra letters columns as needed.

-- A reader asked about dietary supplements. “My doctor recently told me to stop taking probiotics and fish oil,” he wrote. “But my wife and I have been taking them for many years. What say you?” Probiotics and fish oil are among the most popular supplements. Our own preference is that these nutrients be obtained through food-based sources. Fermented foods like sauerkraut, kefir, yogurt, kombucha and miso all contain beneficial strains of bacteria. They’re also less costly than supplements. The same goes for fish oil. It's better -- and more delicious -- to get your omega-3s by eating fatty fish like salmon, mackerel, sardines, herring and black cod. If you’re buying a probiotic, please choose those with as many diverse strains as possible. But our firm belief is that a pill cannot replace a balanced, healthy diet.

-- Along those same lines, a reader asked about vitamin D. “I take 1,000 international units of vitamin D3 daily in two forms -- a tablet and a gel cap,” he wrote. “Is there any advantage of one form or the other?” Vitamin D3 is better absorbed than D2. When it comes to tablets versus gel caps, there’s no difference. It’s important to note the upper limit is 5,000 IU daily. We advise getting vitamin D through dietary sources, including fortified dairy, mushrooms and fish. And, if there’s no skin cancer risk, a bit of daily sunshine.

Elizabeth Ko, MD and Eve Glazier, MD

-- We’ve been getting an important coronavirus vaccine question from a number of readers who are in treatment for cancer, or who are otherwise dealing with a weakened or compromised immune system. A reader in Naples, Florida, said that soon after her husband became fully vaccinated, a cancer diagnosis meant he began immunotherapy and chemotherapy, which suppress the immune system. “Do you have any information on how much protection cancer patients have?” she asked. “Interestingly, the CDC didn’t mention this group in their latest publicized guidance. I think it would be an important issue for your column to address, as there are many cancer patients, unfortunately.” Due to the need to first confirm that the vaccines work in people with healthy immune systems, the initial COVID-19 vaccines studies did not include those who were immunosuppressed. And because we are still in the early stages of the vaccine rollout, it’s not yet clear how effective the vaccines might be in these groups of people. Although it’s possible the vaccines may not be as effective, it is still strongly recommended that most cancer patients, who are at increased risk from COVID-19, get the vaccine. Even a modicum of protection is better than none at all. Unvaccinated cancer patients should be sure to discuss the risks and benefits of the vaccine with their oncologist.

Thank you, as ever, for taking the time to write to us. Please continue to take appropriate precautions against the coronavirus and, if you’re eligible but haven’t yet done so, please get the vaccine.

(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA 90025. Owing to the volume of mail, personal replies cannot be provided.)