Whole grain consumption impairs zinc absorption
I completely agree with Professor Colquhoun who can’t see the point of publishing this questionable study.1 It makes no sense to claim that eating seven servings of whole grains each day is healthy. The very basis of a health giving Stone Age Diet is a varied consumption of meat, fish, vegetables and fruit. Wheat, corn, rye and cow’s milk are common food allergens increasing the risk of headache, migraine and hypertension and arthritis.2,3
It is not enough to recognize that whole grains have more nutrients than processed grains because eating excess grains of any type can interfere with the gut absorption of nutrients.4 For example, I remember a lecture from Professor Nick Solomons. His team had found that a meal of oysters quickly raised serum zinc levels but adding beans halved the increase. When beans plus corn were added to the oysters there was no increase at all in serum zinc.
Much of the inadequacies of modern diets has been blamed on excessive consumption of refined carbohydrates. However, Solomons and colleagues found no significant differences in absorption of zinc absorption in Guatemalan schoolchildren children fed low-phytate maize, either the isohybrid wild-type maize or a local maize.5
Damien Downing reviewed the history of Man’s diets.6 The apes from which we evolved had predominantly fruit-based diets 8 to 10 million years ago. The hominids then introduced starchy root vegetables. Two million years ago we started to eat more meat but it was not until 5000 years ago that dairy products and cereal became an important part of human diets. Advising patients to use a varied high protein stone age diet is the basis of drug-free management in my experience.
1 Aune D, Keum N, Giovannucci E, et al. Whole grain consumption and risk of cardiovascular disease, cancer, and all cause and cause specific mortality: systematic review and dose-response meta-analysis of prospective studies. BMJ 2016;353:i2716.
2 Grant ECG. Food allergies and migraine. Lancet 1979;1:966-69.
3 Darlington LG, Ramsay NW. Review of dietary changes for rheumatoid arthritis. Brit J Rheumatology 1993; 32:507-14.
4 Burk RF, Solomons NW. Trace elements and vitamins and bioavailability as related to wheat and wheat foods. Am J Clin Nutr. 1985 May;41(5 Suppl):1091-10
5 Mazariegos M1, Hambidge KM, Krebs NF, Westcott JE, Lei S, Grunwald GK, Campos R, Barahona B, Raboy V, Solomons NW. Zinc absorption in Guatemalan schoolchildren fed normal or low-phytate maize. Am J Clin Nutr 2006 Jan;83(1):59-64.
6 Downing D. The history of man in four diets. J Nutr Environ Med 2003:13:139-41.
Competing interests: No competing interests