Use Reliable Literature Sources For Information About Vitamins
DEAR DR. ROACH: Would you recommend the most reliable literature source(s) for vitamin and supplement information and interactions? For instance, health magazines give these examples of supplement information:
-- Take magnesium with vitamin D3 for best absorption.
-- Do not take magnesium with zinc or iron supplements. Take it hours apart to avoid poor absorption of the zinc and iron.
-- Take piperine with turmeric/curcumin to enhance their absorption.
-- Take vitamin D3 when taking calcium to improve absorption.
-- Take pine bark extract with L-arginine to stop plaque arterial wall buildup and hardening of the arteries. -- J.L.
ANSWER: The problem with health magazines is that reliable information can be interspersed with information that isn't so reliable. Sometimes a claim is hopeful and based on experimental or animal data; sometimes it is demonstrably false, either by error or to sell an advertiser's supplements. For the examples you mention above, vitamin D (D2 or D3) improves absorption of calcium and magnesium, but this doesn't mean that you need them. I don't recommend them unless they're prescribed.
Piperine absolutely increases the absorption of curcumin, which is the most active ingredient in turmeric. This increases both effectiveness and toxicity. Zinc and iron compete for absorption, so they should not be taken at the same time; if you are deficient, they should be separated. However, neither pine bark nor L-arginine had a benefit on coronary disease in clinical trials.
The first literature source that I recommend is MedlinePlus.gov, which is curated by the National Library of Medicine. It is also part of the National Institutes of Health. Most of the answers above can be found there. Some large institutions, like Johns Hopkins and the Mayo Clinic, have highly reliable information about many medical subjects.
Your local pharmacist is another source, as is your own physician, but some questions require either special expertise or the time and ability to look up the answers.
...continued
