The acne diet—or, more accurately, the acne-free diet—is a way of eating that claims to improve or eliminate acne. There is some debate in the medical community about the impact of diet on acne; however, there is a body of evidence to support the idea that certain foods affect the skin.
By reviewing research from over 40 years, doctors such as dermatologist Dean Goodless have developed a set of recommendations regarding foods that may prevent acne. Goodless presents his recommendations in his book The Acne-Free Diet Plan. He suggests eating a diet low in fat and high in fiber along with avoiding peanut products, fried foods, excessive salt, dairy products, foods high in refined sugars, and high-carbohydrate foods.
Most cultures had folk remedies to help clear the skin, but it was not until the later part of the twentieth century that serious scientific research began to confirm or disprove these folk tales and myths. One of the earliest studies about food and acne focused on chocolate, based on the belief that chocolate contributed to acne. (The study found that chocolate did not increase acne breakouts, and other studies since have confirmed this finding.) Other studies have investigated ethnic groups and communities where there is little or no incidence of acne, such as in the Pacific Islands and Africa. When the diets of these areas were compared to the typical Western diet, there were nutritionally significant differences: the ethnic groups with very low incidence of acne ate predominately plant-based diets that were low in fat and virtually sugar free, whereas the Western diets were heavy in meats, saturated fat, refined sugar, and processed foods. By studying these differences, doctors and researchers developed suggestions for dietary changes to improve or eliminate acne.
Acne is caused when glands in the skin called sebaceous glands begin to form a sticky oil called sebum. These glands are stimulated by hormones that become active at puberty, which is why acne occurs most often in adolescence, when these hormones are produced in abundance. The oils formed by the sebaceous glands hold dead skin cells, preventing them from being sloughed off. As these cells die, they create the perfect environment for bacteria to grow. When these bacteria, called acne vulgaris, become too plentiful, they will attempt to erupt from the skin, causing a pimple. Sometimes, when the bacteria grow, the body sends white blood cells to fight the infection. This natural reaction can cause large, painful cysts to form in the deeper layers of skin.
Opinions vary in the medical community as to whether or not diet plays a significant role in acne. Some dietary changes that have been proposed to help prevent acne breakouts include:
- Eat 20 to 30 grams of fiber every day. Fiber helps keep the colon clean and may remove toxins from the body before they reach the skin.
- Eat a low-fat diet. High fat consumption may elevate hormone levels in the body that cause blemishes on the skin.
- Avoid peanut products. Peanut products were found to cause acne flare ups in a study of 500 adolescents.
- Avoid fried foods.
- Limit salt intake, especially table salt or iodized salt. Many people with acne have elevated levels of iodine, found in table salt, in their bloodstream during acne flare-ups.
- Avoid dairy products such as milk, cheese, and ice cream.
Other vitamins and minerals proposed to affect acne include vitamins A, E, and B; selenium; zinc; omega-3 fatty acids; and chromium.
Many high-carbohydrate foods are believed to worsen acne, due to the spike in blood sugar caused by eating white sugar or refined carbs. This spike raises the level of insulin in the body, and elevated insulin levels may increase production of acne-causing hormones. However, some carbohydrates, such as those made with whole grains, digest more slowly than others, causing a gradual (as opposed to rapid) rise in blood sugar after eating. A system known as the glycemic index ranks carbohydrates and other foods according to the effect they have on blood sugar.
The glycemic index ranks foods based on a scale of 0–100. Foods with higher glycemic index ratings break down quickly and cause a sharp spike in blood sugar. When blood sugar rises quickly, the body produces a surge of insulin to lower the amount of glucose (sugar) in the blood. Insulin is a hormone that helps the body take glucose out of the bloodstream and put it into cells, where it can be used for energy or stored in fat. Foods with lower glycemic index ratings break down more slowly and cause a more gradual rise in blood sugar, meaning that less insulin will be needed.
Foods that have a high glycemic index rating include:
- white bread
- white rice
- white potatoes, depending on how they are cooked
- corn products and some products containing refined sugars
Foods with moderate glycemic index ratings include:
- whole grain breads and pastas
- brown rice
- sweet potatoes
- green peas
- many fruits (especially when eaten alone)
Low glycemic index foods may be enjoyed often without worsening acne. These include:
- rye grain
- legumes such as black beans and lentils
- green vegetables
Foods that are high in fiber tend to have lower glycemic index numbers, because fiber takes longer to digest. Studies have shown that the presence of healthy fats, such as olive oil, can also slow digestion and keep blood sugar from rising too quickly.
Eliminating certain foods from the diet and increasing the amount of specific vitamins and minerals may help reduce the amount of sebum produced and prevent acne breakouts. However, the interaction between diet and acne is not a simple cause-and-effect relationship—if an oily food is eaten, the oil does not travel to the skin or cause it to be oily. However, high levels of fat in the blood may effect the production of hormones such as testosterone, and higher levels of hormones may cause acne to worsen.
Habits such as limiting sodium, processed foods, and saturated fats (found in fried foods) and increasing intake of whole grains, vegetables, and fiber are in line with federal dietary recommendations and support overall health. However, foods such as fruits and low-fat dairy products provide important nutrients like calcium and vitamin C, and eliminating entire food groups could potentially lead to vitamin or mineral deficiencies. People interested in the acne diet should consult with a physician or registered dietitian before starting the diet.
Some acne diets suggest zinc or vitamin A supplementation. People should always consult with their physicians before taking any supplements or other drugs. Zinc supplements can cause stomach upset, and authors of acne diet plans recommend no more than 30 mg of zinc per day to avoid this.
Pregnant women or those who may become pregnant should not take vitamin A supplements or any medications containing vitamin A, as excessive amounts of vitamin A may cause birth defects.
Limiting the amount of dairy products in the diet may limit the amount of calcium consumed. A calcium supplement may be needed to ensure that daily dietary calcium requirements are met.
Dietary supplements could potentially interact with medications prescribed for acne. Some acne medications contain retinol, a form of vitamin A. Taking a vitamin A supplement with these prescriptions can cause a dangerous buildup of vitamin A in the body.Dietary supplements
There are few risks associated with an acne diet. Most relate to taking dietary supplements. Zinc may prevent the body from absorbing enough copper. To avoid this, consumers should look for supplements that specifically state that they do not prevent copper absorption.
Vitamin A is a fat-soluble vitamin. That means that excess vitamin A is stored in the body rather than eliminated in the urine. Many acne prescriptions contain concentrated forms of vitamin A, but too much vitamin A can be toxic. Consult a doctor before taking vitamin A supplements.
RESEARCH AND GENERAL ACCEPTANCE
There is no consensus on whether or not diet plays a role in causing or preventing acne. Many dermatologists do not believe that diet has a significant effect on acne. Early studies about diet and acne focused on specific foods believed to trigger acne breakouts. Most of these studies found no evidence that individual foods cause acne.
Studies of the diets of ethnic groups that have a low incidence of acne form the basis of most of the acne diets. Studies of the diets of tribes in New Guinea, Paraguay, and the Bantu of South Africa, all of whom have little or no acne, found that they ate a primarily plant-based diet. Similar studies on populations in Japan and Korea support these findings.
A 2005 study of over 45,000 nurses claimed a link between the amount of dairy products consumed and severity of acne; women who reported consuming higher amounts of dairy products also reported more severe acne. However, of the women who drank at least two glasses of milk a day, only 8% experienced more severe breakouts.
The theory with the strongest support is that foods high on the glycemic index contribute to acne. Studies have shown that half of acne patients tested had abnormal glucose levels, and in another study, 80% of premenstrual women with acne had abnormal glucose metabolism. This data and others that show a high-carbohydrate diet increases the levels of testosterone in the blood have led to the recommendation of limiting consumption of refined carbohydrates as a means of treating acne.
Several studies have compared the results of zinc supplementation with oral antibiotic therapy to resolved acne and found zinc to be almost as effective as the antibiotic tetracycline.
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American Academy of Dermatology, 930 E Woodfield Rd., Schaumburg, IL 60173, (847) 240-1280, (866) 503-SKIN (7546), Fax: (847) 240-1859, MRC@aad.org, http://www.aad.org.
Deborah L. Nurmi, MS