The alkaline diet seems to be the latest buzz word. But does it live up to its promise?
What is the alkaline diet?
The alkaline diet promotes consuming mainly vegetables and fruit and some ancient grains (considered alkaline foods) and limiting protein-rich foods and most grains (considered acidic foods), in an attempt to limit the production of excess acid in the body. The diet is based on the hypothesis that exposure to excess acid is detrimental to health and leads to diseases such as cancer, diabetes, and cardiovascular disease. Proponents say excess acid needs to be buffered by drawing calcium from the bones, depleting bones and increasing the risk of osteoporosis.
Do I need to worry about eating acid or alkaline foods?
No. Following an alkaline diet does not change the blood’s pH from its normal range. Our body is incredibly capable of maintaining the blood pH level (the measure of acidity) at 7.4, regardless of what we eat. Regulation is done by excreting excess acid in the urine. Although the urine pH will vary based on the types of foods and beverages consumed, it is not an indicator of the acid level in blood. Excess acid in urine is not associated with calcium loss.
Does following the alkaline diet make sense?
There is no evidence that a diet high in acidic foods (such as protein-rich foods) is detrimental to bone health. In fact, based on newer research, we know that protein is actually critical to maintaining bone health. There is also no evidence that an alkaline diet maintains calcium balance and protects bones or that it prevents or cures cancer or diseases such as diabetes and cardiovascular disease.
It is important to eat a variety of foods from all four food groups, in the amounts recommended by Canada’s Food Guide. This will help ensure we get enough nutrients to achieve and maintain health, and more specifically meet our needs for protein and calcium.
By Rola Zahr, MPH, RD
References
- Fenton TR, Tough SC, Lyon AW, Eliasziw M, Hanley DA. Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill’s epidemiologic criteria for causality. Nutr J. 2011 Apr 30;10:41. Abstract available from: http://www.ncbi.nlm.nih.gov/pubmed/21529374 6.
- Cao JJ, Pasiakos SM, Margolis LM, Sauter ER, Whigham LD, McClung JP, et al. Calcium homeostasis and bone metabolic responses to high-protein diets during energy deficit in healthy young adults: a randomized controlled trial. Am J Clin Nutr. 2014 Feb;99(2):400-7. Abstract available from: http://www.ncbi.nlm.nih.gov/pubmed/24284444 7.
- Cao JJ, Johnson LK, Hunt JR. A diet high in meat protein and potential renal acid load increases fractional calcium absorption and urinary calcium excretion without affecting markers of bone resorption or formation in postmenopausal women. J Nutr. 2011 Mar;141(3):391-7. Abstract available from: http://www.ncbi.nlm.nih.gov/pubmed/21248199 8.
- Hunt JR, Johnson LK, Roughead FZK. Dietary protein and calcium interact to influence calcium retention: a controlled feeding study. Am J Clin Nutr. 2009 May;89(5):1357-65. Abstract available from: http://www.ncbi.nlm.nih.gov/pubmed/19279077