Over the last couple of years you may have heard various bits and pieces floating around about the alkaline diet. Victoria Beckham, Kelly Ripa and Elle Macpherson are just a few celeb alkaline diet enthusiasts. But is there actually any science behind this increasingly popular eating pattern? Here’s my research-backed take on the most basic of diets (pun intended):
What Is The Alkaline Diet?
Contrary to popular belief the alkaline diet is not related to the pH of food itself, but the effect food has on urinary pH [1]. High acid foods lower urinary pH, while alkalizing foods restore urinary pH to normal.
Studies suggest that habitually consuming high acid foods may interfere with normal cellular metabolism, increase calcium excretion, elevate stress hormone levels, and change insulin activity (among other things) [1,2]. Many of these changes have been linked with chronic disease, which has prompted much interest in the alkaline eating pattern.
Which Foods Are Alkalizing?
High protein diets, low in fruits and veggies and rich in salty foods are typically the worst offenders for acid load. Conversely, plant-based foods such as fruit and veggies raise pH and have an alkalizing effect. Following an alkaline diet means consuming mostly foods on the left hand side of the table, and minimizing high acid choices.
**For a comprehensive list of acidifying and alkalizing foods, take a peek at this handout.
The Alkaline Diet and Chronic Disease
#1: Type 2 Diabetes
Several cohort studies indicate that consuming a high acid load diet increases type II diabetes risk and insulin resistance however it’s unclear if eating a diet rich in alkalizing foods remedies this effect [3]. More research is needed before a definitive conclusion about the relationship between the alkaline diet and type II diabetes can be drawn.
#2: Osteoporosis
The jury is still out on this one. High acid load eating patterns increase urinary calcium losses, but it’s unclear if this translates into poor bone health. Several high acid foods such as milk are rich in calcium, phosphorous and vitamin D which are all important nutrients for bone maintenance [2,4]. Like many other diseases, osteoporosis is multi-factorial and risk is influenced by genetics, activity, and hormonal status, as well as diet.
#3: Kidney Stones
High acid load is a risk factor for two different types of kidney stones: calcium stones and uric acid stones. In both cases, limiting animal protein and salt, and consuming a diet rich in plant-based foods is recommended [5].
#4: Cancer
This one has received much attention because an acidic extracellular space around cancer cells has been linked with more invasive forms of cancer [1]. In addition, consuming high acid foods appear to induce several metabolic changes that may lend to cancer development [1].
However, at this point a low protein diet is not recommended for cancer prevention and acid load is not considered a strong predictor of cancer [1]. The acidic environment around cancer cells is generated by tumor cells rather than dietary acid load. Stay tuned for more developments on this topic—there is still much to be learned about the relationship between acid load, alkaline foods and cancer.
Final Thoughts:
Without a stronger body of research, it’s too early to recommend the alkaline diet as an intervention or preventative strategy for chronic diseases such as cancer, diabetes and osteoporosis. A strict alkaline diet is unlikely to be healthiest approach to nutrition because it skips-out on important food groups such as whole grains and lean proteins, which support muscle-building, tissue repair, energy production, and satiety. There is, however, something to be said for making plants the stars of your plate, and giving protein and carbs a smaller slice of the action.
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References:
[1] Examining the relationship between diet-induced acidosis and cancer. Robey IF. Nutr Metab (Lond). 2012 Aug 1;9(1):72.
[2] Diet-induced metabolic acidosis. Adeva MM, Souto G. Clin Nutr. 2011 Aug;30(4):416-21. doi: 10.1016/j.clnu.2011.03.008. Epub 2011 Apr 9. Review
[3]The role of dietary acid load and mild metabolic acidosis in insulin resistance in humans. Williams RS, Kozan P, Samocha-Bonet D. Biochimie. 2016 May;124:171-7.
[4] Causal assessment of dietary acid load and bone disease: a systematic review & meta-analysis applying Hill’s epidemiologic criteria for causality. Fenton TR, Tough SC, Lyon AW, Eliasziw M, Hanley DA. Nutr J. 2011 Apr 30;10:41.
[5] Treatment and prevention of kidney stones: an update. Frassetto L, Kohlstadt I. Am Fam Physician. 2011 Dec 1;84(11):1234-42. Review.
