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