Q: In your column on “Good Fats vs. Bad Fats,” you said that one way to cut down on saturated fats is to replace red meats (beef, pork, lamb) with white meats (chicken and fish).

I’ve been under the impression it was OK to eat pork and lamb in moderation, but to avoid beef and to make up for it by taking vitamin B12. Is this correct?

A: Lean-cut beef, in moderation, is also OK in most diets.

However, avoiding beef is unlikely to put you at a shortfall for vitamin B12, as you seem to think. B12 is present in most animal-derived foods, including pork and lamb, chicken and fish, and eggs, cheese, milk, and milk products.

Let’s take a closer look at this key vitamin.

Unlike other water-soluble B vitamins, the body stores B12 for long periods of time, so most people are not likely to become B-12 deficient.

However, long-term vegetarians could be at risk for B12 deficiency, particularly “nondairy” (total) vegetarians. B12 supplementation is recommended for this group.

A daily multivitamin-mineral tablet provides general nutritional insurance, and typically contains 6 mcg of B12, an amount sufficient for most people (the adult RDA is 2.4 mcg).

Older adults, however, may need more.

With aging, the stomach produces less acid. Adequate stomach acid is required to free vitamin B12 from its dietary protein-bound form so it can be absorbed by the body.

That’s why, for those older than 50, I generally recommend at least 25 mcg of supplemental B12 daily. This amount can be found in multivitamin products promoted for seniors such as Centrum Silver or store brands of the same formulation. Vitamin B-complex and vitamin B12-only supplements provide higher amounts.

Because drugs taken for stomach ulcers reduce stomach acid, long-term users may be at risk for B12 deficiency and so may benefit from B12 supplementation. These drugs include H2 blockers such as cimetidine

(Tagamet) and proton pump inhibitors such as omeprazole (Prilosec, Losec). Similarly, those on metformin (e.g., Glucophage, Glucovance, Avandamet, Metaglip) for type 2 diabetes should be aware that this drug might cause malabsorption of B12. Of special concern is the finding in one study that metformin-induced B12 malabsorption could persist after the drug is stopped.

Another study found that calcium supplementation could partially reverse this effect (researchers think metformin might interfere with calcium-dependent intestinal absorption of B12).

For this reason, people on long-term therapy with metformin might wish to shore up their calcium and B12 intake with supplements. Medical monitoring of vitamin B12 status is also advisable.

Bonus: Reader response has sparked a number of columns on the hot topics of cinnamon and fish oil. Many of you report clipping some of these to send to family and friends who don’t get my column. Due to the overwhelming number of requests from readers who missed one or more of these recent columns, I’ve posted all eight on the Web at http://myweb.cableone.net/rharkn/index.htm.

Please let me know if you find this method useful.

Richard Harkness is a consultant pharmacist, natural medicines specialist, and author of eight published books. Write him at 1224 King Henry Drive, Ocean Springs, MS 39564; or rharknaol.com. Selected questions will be used in the column.

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