Many alternative health practices advocate eating foods that “alkalize” the body’s pH in order to prevent illness. Values for pH range from zero, which indicates maximum acidity, to 14, which indicates maximum alkalinity. Plain water is neutral with a pH of 7. Whether food itself is acidic or alkaline is not a factor in our physiological pH because everything becomes acidic when mixed with hydrochloric acid in the stomach, and alkaline — or basic — in the small intestine. The correct terminology, then, is acid-forming vs. alkaline-forming foods. Minerals and other components of many foods form acidic or alkaline compounds during their metabolism.
Maintaining Blood pH
Your blood and other body fluids must be strictly maintained at a slightly alkaline pH, or you become seriously ill. In the absence of serious metabolic disease, the pH of your blood is automatically regulated in the range of 7.35 to 7.45, no matter what you eat. The kidneys, lungs and dietary minerals do this for you. However, a high intake of acid-forming foods relative to alkaline-forming foods has been linked to osteoporosis because one of the ways the body corrects excess acidity is to recruit calcium from bone. A study published in “Osteoporosis International” in 2001 found preliminary evidence that increasing the intake of alkaline-forming foods may help to preserve bone calcium.
Animal foods, which are concentrated sources of protein, are highly acid-forming foods. Eating large quantities of meat, fish, poultry, eggs and cheese might result in a surplus of amino acids, as well as the mineral sulfur, that form acidic compounds during normal metabolism. Refined carbohydrate foods such as pasta, packaged cereals and sugars are also highly acid-forming. Other acid-forming foods are: most legumes such as beans, lentils and peanuts; most grains such as wheat, rye, rice, oats and corn; some nuts such as cashews; alcohol; coffee; and tea.
Most fruits and just about all vegetables are alkaline-forming. A few exceptions are cranberries and blueberries, which are somewhat acid-forming. Ironically, acidic fruits such as lemons and limes are actually alkaline-forming once metabolized. Fruits and vegetables are good sources of minerals such as potassium, magnesium and calcium that participate in regulating the pH of body fluids and correct excess acidity. “Nutrition Journal” published a study in 2009 in which subjects increased the pH of their blood and urine by taking supplements containing these minerals. Food is preferable, however.
A Matter of Balance
A balanced diet should combine nutritious acid-forming foods with alkaline-forming foods. Although there may be health benefits to increasing alkaline-forming foods, there is no evidence that eliminating-acid forming foods will cure or prevent diseases such as cancer, as some proponents claim. In fact, such a diet can be deficient in protein and other nutrients. Balancing acid-forming foods such as meat with fresh alkaline-forming fruits and vegetables is key. An abundance of alkaline-forming foods, in addition to protecting bones, might also prove to have further benefits such as preserving muscle mass.