Michael Greger MD

Michael Greger MD

Posted January 14, 2012

Published in Health

  • digg
  • Delicious
  • Furl
  • reddit
  • blinklist
  • Technorati
  • stumbleupon

Ask the Doctor: Q&A with Michael Greger, M.D. (Week 16)

Read More: allergies, cancer, cheese, children, chocolate, coffe, dairy, DHA, ear infections, eggs, fish, Heiner Syndrome, ice cream, iron, meat, moringa, pregnancy, soy milk, tannins, tea, vitamin B12, vitamin K

Get VegSource Alerts Get VegSource Alerts

First Name


Email This Story to a Friend

This is another sampling of the more than 800 comments and questions I’ve responded to at the site (so far!). Please feel free to leave any follow-up questions there on any of the hundreds of videos on the more than a thousand topics covered on And remember, there’s a new video posted every weekday, so to make sure you don’t miss any:

Judy0520 asked on Ask the Doctor (Week 15)A booth at our farmers’ market is selling moringa. It is a nutrient based plant, exceptional supplementation. It is touted to be “nature’s perfect food.”. Opinions please.

I had to look that one up! I assume they’re talking about Moringa oleifera. There are a few in vitro studies (meaning in a test tube or petri dish outside of the body) showing that leaf extracts may have antiproliferative effects on human cancer cells (as has been shown with cabbage and onion family vegetables–see my #1 anticancer vegetable video). And of course there’ve been nonhuman animal studies but I was unable to find any clinical studies (meaning done with actual people).

Based on nutrition analyses it appears to be quite nutritious, though: in comparison with other foods, various parts of Moringa oleifera have more iron than spinach (5.3-28.2 mg  vs 2.7 mg in spinach), more vitamin C than oranges (120-220 mg vs 69.7 mg per orange), and more potassium than bananas (1324 mg  vs 422 mg per banana). The calcium content in the leaves of Moringa oleifera is also really high but I don’t know about the oxalate content. Bottom line: if it’s comparable in price to other healthy vegetables like broccoli I’d give it a try unless you’re pregnant or trying to get pregnant, as it has been noted to have antifertility and abortifacient properties.

Ericjay asked on Ask the Doctor (Week 13)Hi doc. Any research studies on dairy consumption and ear infections in children. My friend’s child had numerous ear infections and I recommended soy milk instead of cows milk plus to eliminate cheese, ice cream, etc. She asked a chief pediatric ENT at a big hospital who of course said there is no connection. Of course, if there were he wouldn’t make as much money so I’m sure he wouldn’t push that subject to anybody. This child incidentally was on numerous rounds of antibiotics and may have tubes inserted in her ears. I thought she should give it a try. Thanks Eric.

The association between cow milk exposure and recurrent ear infections in susceptible children has been documented for 50 years. Though there are rare cases of pathogens in milk causing ear infections directly (then meningitis), the link is thought to be due to milk allergies. In fact there’s a respiratory disease called Heiner Syndrome, a lung disease of infants primarily caused by milk consumption that can cause ear infections. Though milk allergy most often results in respiratory, gastrointestinal, and skin symptoms, as many as 1 in 500 may suffer speech delay due to chronic inner ear inflammation. For 40 years there’s been a recommendation to try “a 3 month trial on a strict cow’s milk elimination diet” for children with recurrent ear infections, but Dr. Benjamin Spock, probably the most respected pediatrician of all time, ended up recommending a life-long elimination of cow’s milk. See my video: Doctors’ Nutritional Ignorance.

hcdr asked on American vegans placing babies at riskI feel our family has a healthy and complete diet (in no small part thanks to you!) but do you have any specific recommendations or guidelines for those who would like to follow a vegan diet through pregnancy, infancy and childhood? Is the most important thing (apart from healthy, whole foods) kid-friendly B12 and DHA, and probably D?

There are two great new resources for those who want to raise their families on plant-based diets: one by Reed Mengels and one by Jack Norris and Ginny Messina. Ask for them at your local library.

vjimener asked on Better than green tea?I have read in a magazine that there are several types of vitamin K. According to the article, Vitamin K1 is found in vegetables. Vitamin K2 mk7 is found in meat, fish and eggs. The article also said that Vitamin K1 is stored in the liver for only one hour, time not enough to perform all its tasks. On the contrary, vitamin k2 mk7 would stay in the liver for the whole day. So my question is: should vegetarians take supplements of vitamin k2 mk7 (created from natto)?

Not sure what magazine you were reading, but the scientific consensus is that either one (menaquinone or phylloquinone, formerly K1 and K2) is fine for maintaining human vitamin K status. The recommended intake is about 100 mcg. A half cup of kale? >500. No need for natto; just eat your greens. In fact dark green leafies are so packed with vitamin K that if you’re on the drug coumadin (warfarin), a drug that works by poisoning vitamin K metabolism, you have to closely work with your physician to titrate the dose to your greens intake so as to not undermine the drug’s effectiveness! Learn more about the wonders of greens in my 25 videos.

ksduck asked on Dried apples versus cholesterolThis is a bit unrelated, but I eat a plant-based diet. I’m also a 20-something year old woman of child bearing age who runs, so making sure I’m getting enough iron from plant sources is important to me. I’ve heard that tannins in coffee, tea, and chocolate can hinder the adsorption of iron when consumed together. Is there evidence to support this? Thank you!

Quoting from “Green tea does not inhibit iron absorption” published 2009 in the International Journal of Cardiology, “The only reference that I could find in the literature about a negative effect of tea drinking on iron absorption came from Tunisia. But the experiment was carried out on rats. Therefore, unless you are a rat and a rat in Tunisia, you should not worry about development of iron deficiency anemia from tea drinking.”

In 2008, though, a study in India found that drinking tea with meals could cut iron absorption in half. This is a function of publication delays. The cardiology journal piece was published in 2009 but was written in 2007, before the India study surfaced. The good news, though, is that the study found that vitamin C triples iron absorption, so as long as you’re drinking tea with lemon, or eating vitamin C rich foods at your meals (like citrus, broccoli, tropical fruits, bell peppers, etc.) then this shouldn’t be an issue. If, however, you don’t like lemon (and lemon in coffee? Yuck!) and aren’t eating these kinds of foods, then menstruating women may want to lay off tea and coffee (and cocoa and peppermint tea) during meals and up to an hour before to maximize iron absorption. In men (and nonmenstruating women), the reduction of iron absorption may not necessarily be a bad thing. In fact, the effect of coffee on iron absorption has been used to explain why coffee consumption has been found to be protective against diseases tied with iron overload such as diabetes and gout.

-Michael Greger, M.D.