The alkaline diet has been gaining in popularity, amid claims that eating
acid-forming foods compared to alkaline-forming foods promotes metabolic imbalances that lead to chronic diseases. Foods do not significantly influence the body's pH, because the acid/base balance is very tightly regulated. However, the buffer system regulating the body's pH may compromise your bone health by trying to balance the effect of an acidic diet.
Acidic Foods
A model to estimate the impact of food on urine acidity was published in the July 1995 issue of the Journal of the American Dietetic Association. A positive PRAL--potential renal acid load--score indicates a food has an acid load, and a negative value represents an alkaline load. According to this model, meat, poultry, fish, eggs, cheese, milk, chocolate milk, yogurt, peanuts, walnuts, grain products, butter and cola have the highest PRAL values and therefore are acid-forming foods.
Alkaline Foods
Negative PRAL scores, which represent the alkaline-forming potential of foods, were found almost exclusively in fruits and vegetables. The foods with the most alkaline-producing potential were raisins, black currants, bananas, apricots and kiwi fruit in the fruit category, and spinach, celery, carrots, zucchini and cauliflower in the vegetable category. Red and white wine, cocoa made with semi-skim milk and mineral water also were found to be alkaline producing.
Bone Health
Acid-producing foods widely consumed in today's Western diet can have a detrimental effect on bone health and may lead to the development of osteoporosis, according to registered dietitian Dina Aronson in Today's Dietitian. The body needs to release minerals to buffer and neutralize its pH, and if alkaline foods are not consumed in sufficient amounts, stored minerals from the bones will be used. which can decrease bone density. On the other hand, alkaline-forming foods such as fruits and vegetables are associated with improved bone health.
Cancer
Some in vitro studies showed that cancer cells proliferate at a faster rate in an acidic solution and that some chemotherapy drugs were more effective in an alkaline environment, according to dietitian Stephanie Vangsness from the Dana-Farber Cancer Institute and Brigham and Women's Hospital. Unfortunately, these observations have not been replicated with human clinical trials, and there is therefore no scientific evidence to support an alkaline diet for cancer prevention. However, because the most alkaline-forming foods are fruits and vegetables, it is a wise idea to include more of them in your diet. Although their alkaline properties may not influence your cancer risk, their high antioxidant content will help you stay healthy.
Healthy Weight
Proponents of the alkaline diet claim that basing 75 to 80 percent of your diet on alkaline-producing foods can help you achieve a healthy weight. Although this has yet to be proven scientifically through randomized clinical trials, the abundance of vegetables and fruits in the alkaline diet can certainly help you reach you weight loss goals more easily. To lose weight, you must consume less calories and lower your calorie intake without feeling overly hungry. Eating more fiber-rich foods like fruits and vegetables can be helpful, as explained by Barbara Rolls in the July 2009 issue of Physiology & Behavior. People consuming more nonstarchy vegetables have increased feelings of satiety, which facilitates weight loss. It led to significant weight loss in the study's participants, even without counting calories.
References
- Todays's Dietitian: Ask the Expert
- The Journal of the American Dietetic Association: Potential renal acid load of foods and its influence on urine pH
- Brigham and Women's Hospital: Alkaline Diets and Cancer: Fact or Fiction?
- Physiology & Behavior: The relationship between dietary energy density and energy intake
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