The alkaline diet - what is it? The theory goes a little something like this: A diet rich in acid-producing foods can lead to mineral loss and disease as the body taps into nutrient stores to restore homeostasis. Thus, the solution would be to protect body's health and balance by eating more alkalinizing foods. 2
Are there any sizeable, well-designed clinical trials to demonstrate the effectiveness of the alkaline diet for health?
Unfortunately, not yet.
While there are theories that foods can influence the body’s pH, the truth is that cell and blood pH must stay tightly controlled. Life depends on appropriate pH levels. Because it is so important, the human body tightly controls pH levels in the blood at about 7.4 (this is slightly alkaline but the range is from 7.35-7.45).
An interesting side note: the importance of pH in soil. If soil pH is too acidic (below 6), minerals are used up as buffers to maintain pH. Thus, acidic soils tend to have less calcium and magnesium. This can influence the mineral content of the plants that become the food we eat. Typically, manure is added to acidic soils to raise the pH above 6. 1
While blood and cell pH stay tightly controlled, urine pH can vary. One study helped categorize foods according to their acid- or base-forming potential to indicate how these foods can potentially affect urine acidity. It showed that meat, poultry, fish, dairy products, caffeine, sugar, pale beers, cocoa, and salt are the acid promoting foods. Grains were only slightly acid-forming. Fruits, vegetables, fruit juices, potatoes, and alkali-rich, low-phosphorus beverages (red and white wine, mineral soda waters) were the most alkaline forming foods. 3
Urine Acidity Can Change - So what?
Why is this important? Studies suggest that indulging in acid-forming foods causes the body to work harder to neutralize the pH. The pH is mainly neutralized by releasing alkalizing minerals into the blood to buffer the acid. If the diet is low in these minerals, it taps into its biggest storage depot: bone.
The alkaline diet is a specific diet prescription that includes 80% alkaline-forming foods and 20% acid-forming foods. It claims that this ratio helps reduce inflammation and prevent disease. Unfortunately, there are no clinical trials to establish any concrete cause and effect relationships.
Although we do not have much evidence, the principle behind the alkaline diet is definitely not a bad idea. Including more fruits and vegetables is definitely beneficial (for countless health benefits) and is almost always necessary since most diets are deficient.
As aforementioned, a diet low in alkalinizing minerals can lead to borrowing minerals from bone stores. You'll find, hear, and read about many studies regarding acid/base balance, calcium status, and bone health. In part 2, learn more about how alkaline-forming foods can have a positive effect on bone health while the acid load from typical Western diets can be a risk factor for osteoporosis.
1. Songklanakarin Journal of Science and Technologh. 2005;27(supplement 3):727–737.
2) J Environ Public Health. 2012; 2012: 727630.
3) Remer T, Manz F. Potential renal acid load of foods and its influence on urine pH. J Am Diet Assoc. 1995;95(7):791-797.