Some research suggests that following an alkaline diet might improve health in people with kidney disease. However, it does not achieve this by changing blood pH.
Rather, the alkaline diet encourages people to eat more fruits and vegetables and fewer processed meats and high-fat dairy products. For this reason, the alkaline diet may still improve health.
A handful of studies also show that eating low-acid foods improve health, even though they do not increase blood pH.
In this article, we look at claims surrounding the alkaline diet, whether they are true, and how the foods of the alkaline diet can improve health.
Does it work?
It is not possible to change blood pH with diet.
What many people believe to be the main benefit of the alkaline diet is false.
The alkaline diet promotes the false idea that it is possible to change blood pH with diet. This is untrue, and major changes in blood pH could even be life-threatening.
It is possible to change the pH of urine and saliva with diet. However, when the pH of these fluids changes, the pH of blood remains the same.
Alkalinity means that something has a pH higher than 7. The human body is naturally slightly alkaline, with a blood pH of around 7.4.
The stomach is acidic, which allows it to digest food. The pH of saliva and urine changes depending on diet, metabolism, and other factors.
Some research shows that cancer cells grow more rapidly in an acidic environment. Drawing on this research, supporters of the alkaline diet argue that a high blood pH could prevent cancer.
Studies on alkalinity and cancer, however, have typically involved cancer cells in a petri dish and not a human body.
Research on the alkaline diet
No research has shown that the alkaline diet can raise blood pH.
However, some research suggests that an alkaline diet may improve health, though not in the way that its supporters claim. Alkaline diets reduce a person's consumption of fatty and processed meats, and they encourage people to eat more fruits and vegetables. This offers several health benefits.
Here are some of the benefits that alkaline diet supporters may claim, and the scientific research either supporting or refuting them:
Promoting weight loss
Many strategies can help people lose weight.
Ultimately, weight loss depends on consuming fewer calories than one burns. Diets lower in fat and calories may promote weight loss, but only when a person remains physically active and eats a healthful diet with variety.
An alkaline diet tends to be low in calories, so it may help people lose weight.
Improving kidney health
Raising urine pH may improve health for some people.
According to a 2017 study, the typical diet of people in the United States is very acidic. This can challenge the kidneys. For people with kidney disease, a lower-acid diet may improve symptoms or even slow the course of the disease.
Some proponents of this diet claim that it can reverse cancer or support chemotherapy. There is no scientific evidence supporting these claims, and no studies have performed direct tests on this claim.
However, significant evidence from a 2010 study suggests that reducing meat consumption and eating more fruits, vegetables, and whole grains might prevent cancer.
The study looked at data from the 2010 European Prospective Investigation into Cancer and Nutrition. It found that consuming vitamin C, vitamin A, fiber, and a Mediterranean-style diet might reduce cancer risk.
The American Cancer Society (ACS) recommend a diet similar, but not identical, to an alkaline diet. The ACS advise avoiding processed foods, soft drinks, and many high-fat foods. Instead, it is more beneficial to eat a diet rich in fruit, vegetables, and whole grains.
Treating or preventing heart disease
An alkaline diet may naturally raise levels of growth hormone, but the research is preliminary and inconclusive. Research finds that growth hormone supports body composition and lowers heart disease risk factors.
Alkaline diets also tend to be low in fat and calories, naturally promoting a healthy body weight and lowering heart disease risk factors. They also reduce or eliminate red and processed meats, removing a major contributor to heart disease from the diet.
Improving growth hormone levels
Better heart health is just one potential benefit of having higher growth hormone levels. Improving growth hormone levels may also promote better brain functioning, particularly memory and cognition.
Some evidence suggests that growth hormone improves overall quality of life.
However, the evidence linking an alkaline diet to increases in growth hormone levels is weak. Some studies have shown that correcting a highly acidic environment with specific supplements such as bicarbonate can promote alkalinity, but this does not necessarily mean that an alkaline diet has similar benefits.
Improving back pain
This research does not directly test the benefits of an alkaline diet, so it is uncertain whether alkaline foods might help with chronic pain.
Osteoporosis is a major risk factor for bone fractures, especially in older people and females. Some proponents of this diet say that it reduces the amount of calcium lost in urine, and that this lowers osteoporosis risk. However, no scientific evidence supports this claim.
That said, eating more fruits and vegetables may improve bone health. Alkaline diets are rich in these foods. They also tend to be low in protein, which supports bone and muscle health.
It is unlikely, therefore, that an alkaline diet can prevent osteoporosis. Extremely low-protein alkaline diets may also be an osteoporosis risk factor. A better strategy is to eat more lean proteins, fruits, and vegetables.
Promoting healthy muscles
People tend to lose muscle mass as they age.
This increases a person's risk of falls and fractures, and it may also contribute to weakness and chronic pain. A 2013 study offers preliminary evidence that an alkaline diet may improve muscle health.
Researchers examined 2,689 females in a long-term twin study. They found a small but significant increase in muscle mass among females following a more alkaline diet.
Alkaline diet foods
Tofu is a low-acid food.
People interested in trying an alkaline diet should eat more low-acid foods.
- legumes, such as lentils
Lentils, tofu, and some seeds are good sources of protein, but it is important to eat enough to make up for the removal of dairy products and meat.
People interested in trying an alkaline diet should avoid high-acid foods. These include:
- dairy products such as cheese and milk
- processed foods
A diet rich in variety is the most healthful option. People should aim for a diet that includes a range of different proteins, grains, fruits, vegetables, vitamins, and minerals.
Removing any single food group or type of food from a diet can make it more difficult for a person to be healthy. Very low-protein alkaline diets may help people lose weight, but they may also increase the risk of other issues, such as weak bones and muscles.
People who wish to try an alkaline diet should ensure that they eat enough protein. Those who are able to eat enough protein on an alkaline diet can safely try it.
While the alkaline diet does not actually change blood pH, it can help people eat a wide range of healthful foods, improving overall health.
People with serious medical conditions or a history of nutritional problems should consult a doctor before trying this diet.