Wednesday, September 8, 2010

Vitamin and Mineral Absorption: Stop Shooting yourself in the Foot

Do you take vitamins and minerals? I do, and I can see a difference when I take them. When I don't, my skin breaks out and generally doesn't look up to par. I had nosebleeds before taking a big dose of zinc every day, and was mildly anemic before taking iron. But I said to myself, I eat a healthy diet. I don't smoke or drink much alcohol. Why don't I absorb more of the vitamins and minerals I eat?

Vitamin and mineral absorption is the problem I'm going to address in this post. There are a lot of everyday foods, drinks, diets and medicines that can make vitamins and minerals pass right through you. I don't want you to give up all your favorite foods and beverages, but consider making some small changes to make the most of your vitamins.

Coffee and Tea. I wrote in my last post that coffee and tea interfere with iron absorption. (By "tea," I'm sure that means camellia sinensis, like black tea or green tea or white tea, not apple-cinnamon-vanilla or peppermint-spearmint tea.) I used to drink tea constantly when I was a kid. I'd have taken in the bottle if it had been offered. My solution now is to wait a few hours after taking my vitamins to have tea or coffee. Next summer, I'll cut back on the iced tea during meals.

Low-Fat Meals. Salad with grilled chicken breast and fat-free dressing is on just about every restaurant menu out there. The problem with this kind of meal is that nutrients like carotene and lycopene don't have any fat to glom onto, and you can't absorb them(1). Likewise, "Fat-soluble vitamins--vitamins A, D, E and K," says Colorado State University,(2) "dissolve in fat before they are absorbed in the bloodstream to carry out their functions." In other words, if you're eating super-vitamin enriched cereal with fat-free milk, or chicken breast salad, you'll pee away all those wonderful vitamins, besides getting a dose of phytic acid with the cereal (see below). The solution is easy: just go ahead and have the full-fat dressing or milk.

Nuts, Grains, Legumes and Other Seeds.
This includes beans, soy, bread, cereals, tortillas, oats, and all those "healthy whole grains" we're encouraged to eat. These foods, which are all basically seeds or beans, contain phytic acid. Phytic acid gloms onto iron(3), calcium, zinc(4) and magnesium (5) and prevents you from absorbing them. Yes, phytic acid is an antioxidant, but if it's leaching minerals from you, its benefits come at a high price. What to do? The Weston A. Price Foundation says that soaking, fermenting and/or roasting(6) these foods reduces the phytic acid. The Foundation adds (7) that a little phytic acid won't hurt you:
Daily consumption of one or two slices of genuine sourdough bread, a handful of nuts, and one serving of properly prepared oatmeal, pancakes, brown rice or beans should not pose any problems in the context of a nutrient-dense diet. Problems arise when whole grains and beans become the major dietary sources of calories— when every meal contains more than one whole grain product or when over-reliance is placed on nuts or legumes. Unfermented soy products, extruded whole grain cereals, rice cakes, baked granola, raw muesli and other high-phytate foods should be strictly avoided.
I make a protein shake every morning with nut butter, rice protein powder and vitamins. I won't worry about it, though, because I'm using just a tablespoon each of the protein powder and nut butter.

Antacids. Acid indigestion is an oxymoron. Think about it: acid breaks down food, which helps you digest it. If you have less acid, you have less digestion. This may explain greater risk of hip fracture(9) (due to possible calcium malabsorption), reduction in Vitamin C(10), and possible magnesium loss(11) all associated with long-term proton-pump inhibitor use. Besides, stomach acid is part of your immune system: most germs die in that acid bath--if you haven't neutralized the acid. I know acid reflux is miserable--I had GERD so bad that it gave me an esophageal ulcer. Going off the PPIs gave me a miserable bout with acid rebound. Adopting a low-carb lifestyle allowed me to stay off the acid blockers and avoid acid reflux.

Given popular notions about what makes for a healthy diet, you might read this and wonder what's left to eat. It's possible to make it out to be harder than it really is. Breakfast especially seems difficult for people. Eggs are a good standby, but so are leftovers, vegetables with homemade ranch dip (sour cream with herbs and spices like Mrs. Dash), bacon, ham, sausage, string cheese, leftovers, or a rice protein powder shake. Have a sandwich with lettuce in place of bread. Eat a naked burrito or make a pizza without the crust (I put the toppings on a plate and microwave them). And there's always soup. Diehard grain and bean lovers can try soaking, roasting and fermenting foods that have phytic acids.


(1) "Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection." Melody J Brown, Mario G Ferruzzi, Minhthy L Nguyen, Dale A Cooper, Alison L Eldridge, Steven J Schwartz and Wendy S White, American Journal of Clinical Nutrition, Vol. 80, No. 2, 396-403, August 2004.

(2) "Water-Soluble Vitamins" by J. Anderson and L. Young1 (Revised 8/08). Colorado State University Extension website.

(3) "Iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate" by L Hallberg, M Brune and L Rossander, American Journal of Clinical Nutrition, Vol 49, 140-144, Copyright © 1989.

(4) "Calcium binding to phytic acid" by Ernst Graf Journal of Agriculture and Food Chemistry, 1983, 31 (4), pp 851–85.

(5) "Phytic acid added to white-wheat bread inhibits fractional apparent magnesium absorption in humans" by Torsten Bohn, Lena Davidsson, Thomas Walczyk and Richard F Hurrell, American Journal of Clinical Nutrition, Vol. 79, No. 3, 418-423, March 2004

(7) "Living with Phytic Acid" by Ramiel Nagel, Friday, 26 March 2010. Weston A. Price Foundation web site.

(8) Ibid.

(9) "Long-term Proton Pump Inhibitor Therapy and Risk of Hip Fracture." By Yu-Xiao Yang, MD, MSCE; James D. Lewis, MD, MSCE; Solomon Epstein, MD; David C. Metz, MD, Journal of the American Medical Association, Vol. 296 No. 24, December 27, 2006.

(10) "Proton pump inhibitors reduce the bioavailability of dietary vitamin C" by
E. B. HENRY, A. CARSWELL, A. WIRZ, V. FYFFE, K. E. L. MCCOLL Alimentary Pharmacology & Therapeutics Volume 22, Issue 6, pages 539–545, September 2005.

(11) Hypomagnesaemia due to use of proton pump inhibitors – a review M.T. Kuipers1, H.D. Thang, A.B. Arntzenius. The Netherlands Journal of Medicine, May 2009, Vol. 67, No. 5, p. 169.


Mike W said...

Lori, brilliant research. Again!

Lori Miller said...

Thanks, Mike.