Alkaline diet

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (April 2012)

The alkaline diet (also known as the alkaline ash diet, alkaline acid diet, acid ash diet, and the acid alkaline diet) is a diet based on the belief that certain foods, when consumed, leave an alkaline residue, or ash, in the body. Elements such as calcium, iron, magnesium, zinc, and copper are said to be the principal components of this "ash". Alkaline-diet proponents thus classify foods as alkaline, acid or neutral according to the pH of the solution created with its ash in water.

Alkaline diets are promoted and marketed primarily by practitioners of alternative medicine, with the claim that such diets might prevent cancer, fatigue, obesity, allergies, osteoporosis, and a variety of other physical complaints and illnesses. ^[1]

The relationship of acid-base homeostasis and diet and disease "has been a subject of considerable speculation for at least several centuries".^[2] Hypotheses include a relationships to bone, kidney stones, and muscle function.^[2]

Although "acid-ash" hypothesis has been considered a risk factor for osteoporosis by various scientific publications,^[3][4] the weight of available evidence does not support this hypothesis.^[3][5][6]

History

D. C. Jarvis attributed "respiratory and other bodily symptoms" to imbalanced pH in 1932.^[7] A similar diet, called the Hay diet, was developed by the American physician William Howard Hay in the 1920s. A related alternative medical system called nutripathy was derived by another American, Gary A. Martin, in the 1970s.^[1] Contemporary proponents of an alkaline diet include Robert O. Young.

Diet composition

In general, the alkaline diet involves eating certain fresh citrus and other low-sugar fruits, vegetables, tubers, nuts, and legumes. The diet recommends avoiding grains, dairy, meat, sugar, alcohol, caffeine, and fungi. Proponents believe that such a diet maintains the balance of the slight alkalinity of blood without stressing the body's acid-base homeostasis.

Disadvantages

Because the alkaline diet promotes excluding certain families of foods, it could result in a less-balanced diet with resulting nutrient deficiencies.^[8]

Scientific evaluation

A selectively alkaline diet has not been shown to elicit a sustained change in blood pH levels, nor to provide the clinical benefits claimed by its proponents. Because of the body's natural regulatory mechanisms, eating an alkaline diet can, at most, change the blood pH minimally and transiently.^[8]

Recent systematic reviews of the published medical literature have found no indication that an alkaline diet can prevent osteoporosis, nor that such diets produce any beneficial effect on bone health whatsoever.^[3][5][6]

There are no studies done in humans that support the use of this diet in treating or preventing cancer. While in vitro (test tube) studies have found that some cancer cells can grow faster under acidic conditions and that chemotherapy drugs may be more effective under alkaline conditions, there is no evidence that this applies in vivo (inside the body) or that alkaline diets can create these types of conditions.^[8]

References