The alkaline diet, which involves eating more alkaline foods-such as fruits and vegetables, with kale and raisins being particular alkaline powerhouses-and reducing your intake of high-acid foods-such as dairy, meat, wheat, fish and carbonated drinks, including soft drinks-claims to help followers reduce inflammation, lower the risk of diabetes, and lose weight. But what's acid and what's alkaline isn't always so obvious. Many vegetables and fruits are more alkaline-including certain foods you might think of as acidic, such as lemons and other citrus, which actually don't produce acid during digestion.
So is there any proof that gearing your diet towards alkaline-based foods is beneficial to your health? Previous research showed mixed results, but a November 2013 study in the journal Diabetologia, followed more than 66,000 women-all teachers in France-over 14 years to see if there was a specific link between what the women ate and their risk of type 2 diabetes. In particular, the researchers wanted to know whether eating foods high in acidity raised the women's diabetes risk, and if eating a more alkaline diet helped protect them against diabetes, one of the biggest killers.
For the first time, the research linked a high-acid diet with an increased risk of developing type 2 diabetes. Even more worrisome, the risk tended to be higher among normal-weight women compared to overweight women.
The question of high-acid versus alkaline foods relates to how the body-and the kidneys, in particular-processes what we eat and drink. "As part of the food breakdown process, some acid is produced; this can be gotten rid of by the body in two ways: breathing out and through the kidneys," explains Deidra C. Crews, M.D., an assistant professor of medicine in the division of nephrology atJohns Hopkins University School of Medicine in Baltimore. "Certain foods lead to a greater amount of acid that needs to be gotten rid of. Generally these are animal-based foods, and more plant-based foods have lower acid content."
When you eat acid-forming foods, try balancing them out by loading up on more alkaline foods. For instance, a kale salad with fish.
How acidic or alkaline a food or drink is can be measured on the pH scale-which runs from zero to 14: a pH of 14 is completely alkaline; a pH of zero is completely acidic; and a pH of 7 is neutral. An ideal, balanced blood pH score for people is about 7.35 to 7.45, or slightly alkaline, which the alkaline diet aims to do.
Although the French study is the first of its kind to determine a possible association between acidity in the diet and type 2 diabetes risk over time, it's not the first to investigate whether there's a link between alkaline/acid diets and health. Other research has found an increased risk of hypertension, some types of kidney stones, lower back pain, and bone loss in people who eat a high-acid diet. It's possible that a high-acid diet causes health problems and that a low-acid diet has health and beauty benefits, such as reducing inflammation, says Dr. Crews. "There's some suggestion that a diet high in acid content may lead to greater inflammation, so having more inflammatory markers in the bloodstream could lead to muscle pain," such as lower back pain, she explains. "So it's conceivable that if you follow a diet that leads to fewer inflammatory cells floating around, you may have better pain control."
Eating a more alkaline diet has benefits on the outside, too, such as helping to improve your skin, according to Jeannette Graf, M.D., an assistant clinical professor of dermatology at Mount Sinai Hospital in New York City and author of "Stop Aging, Start Living: The Revolutionary 2-Week pH Diet That Erases Wrinkles, Beautifies Skin, and Makes You Feel Fantastic." "We have stem cells in the basal layer of the epidermis," she explains. "If we are alkaline, that layer will get the nutrients to produce a healthy epidermis-good blood flow, enzymes are working, mitochondria are happy, and we have a glow. If we are acidic, the stem cells won't have that."
Dr. Graf adds that even if we eat some alkaline foods, it's probably not enough to ensure that healthy glow. "Lifestyle, stress, refined foods, pollution-we're getting a bigger load of acid internally," she explains. "Normally, we have a natural buffer system, but we're overpowering our system, which pulls from mineral stores in our tissues. When we deplete those, we need to pull from our bones and dump excess acid in our organs, so over time we become more acid."
One of the worst culprits, says Graf, is soda. "Cola drinks are the worst," she says. "And smoking is a major acid producer," as are sugar, refined foods, most dairy, meat and most nuts. Her top advice to patients? "I basically tell them to follow a Mediterranean diet, a colorful diet," she says, adding that although shifting to more fruits and vegetables may be a gradual and difficult process, once people make the switch it's not hard to stick with it: "The more alkaline you are, the more you crave alkalinity," she says. "It's contagious."
Bottom line: There's no downside-and there are loads of health and beauty benefits-to upping your intake of fruits and vegetables in general, while reducing your intake of red meat and cutting out sugar (including artificial sweeteners) and soda…but you don't really need a diet to tell you that.