ACNE: DIETARY MYTHS AND FACTS
Acne results from clogged pores in the skin. Sebum, the oily substance secreted by sebaceous glands, mixes with dead cells to form a plug that can become infected. It is characterized by pimples, red bumps, whiteheads, blackheads, cysts, pustules, and nodules. About 80 percent of people experience acne from adolescence to age 30 and it can return in older adults after age 40. Myths persist about chocolate and fried foods causing acne, but there is limited scientific support for any link.

An analysis of 27 research studies published in 2013 examined the connection between diet and acne. The authors concluded that for 15 to 25-year-old males with acne, a diet with a low glycemic load resulted in a decreased number of lesions. These same authors published a subsequent questionnaire study in 2014 of 248 males and females ranging from 18 to 25 years of age. The results indicated that people with moderate-to-severe acne reported a diet with increased glycemic index, added sugar, saturated fat, and fewer servings of fish in comparison with people who had mild or no acne. Foods with a low glycemic index do not create sharp blood sugar spikes as they are metabolized. Excess sugar can contribute to an inflammatory state, and low glycemic foods might prevent this from happening. For conditions that are characterized by inflammation, such as acne, a low glycemic diet might be beneficial.

Dairy products have recently received a high level of attention, especially in relationship to people with acne. Several retrospective studies of affected people suggest that ingestion of milk is associated with the condition. Surprisingly, skim milk in a diet has a higher association with acne than whole milk! The basis for this result is unclear, but might be due to different hormone levels in skim milk or the presence of additives in skim milk, such as whey protein. Alternatively, there may be a difference in the way whole milk is metabolized and the presence of fat in whole milk improves absorption of a beneficial component of milk.

Clear cause-and-effect relationships between diet and acne have not been firmly established for all people with acne and research studies with adults are especially scarce. There are likely to be individual dietary factors along with lifestyle circumstances, such as stress level and quality of sleep, that together impact the condition. A dietary journal can be useful to help people determine which foods are associated with increased acne breakouts.

FOOD TRIGGERS OF ROSACEA FLARE-UPS
Rosacea is a skin condition characterized by facial redness, superficial blood vessels, inflammation, and breakouts. The cheeks, nose, and forehead are commonly affected areas. As many as 10 percent of the United States population is affected and 75 percent are women of middle age (30 to 50 years old). The condition is more common among people of Northern European, English, and Irish descent and 30 to 40 percent of people with rosacea have an affected family member. Scientists are only beginning to understand the basis for rosacea; it seems to involve an imbalance of microbes that populate the skin. Although there is currently no cure, newly available prescription drug treatments have offered many people symptomatic relief.

An important part of rosacea management is awareness of circumstances and foods that can trigger a flare-up. A characteristic of rosacea is intense facial flushing that can occur with exposure to cold or hot temperatures or the "heat" of spicy food. People with rosacea should wait for steaming hot food to cool before eating and avoid hot drinks, such as coffee, tea, and hot chocolate. Other dietary triggers for flushing are alcohol, dairy products, vinegar (such as pickled foods), citrus fruit, eggplant, and spinach.

Many of these foods contain elevated amounts of histamine, a naturally occurring neurotransmitter that causes blood vessels to expand, leading to skin redness and swelling. Histamine is a flavor-enhancing byproduct of fermentation and foods such as cheese and sauerkraut tend to have high levels of the chemical. Other foods can cause the release of histamine from immune cells and produce similar symptoms to a food allergy.

People with rosacea should avoid histamine-rich foods and foods that cause histamine release. Individuals will unlikely be affected by all of these foods; a food diary can help clients identify which ones affect them and what the threshold amount for a reaction.

EDIBLE SUN PROTECTION
Skin contains several chemicals that act as endogenous, ultraviolet protectants and antioxidants. One group of chemicals, carotenoids, is made of highly effective inactivators of molecules that cause oxidative stress. Humans lack the ability to synthesize carotenoids, so they must be supplied by the diet. Caotenoids supply the red and yellow pigments in brightly colored fruits and vegetables; the most common ones in people's diet are alpha- and beta-carotene (precursor to vitamin A), lycopene, beta-cryptyzanthin, lutein, and zeaxanthin.

Nutritional supplements of two carotenoids, beta-carotene and lycopene (red pigment in tomatoes), have been investigated for their benefits to skin. In one clinical trial, volunteers taking either a supplement with beta-carotene or a lycopene-enriched diet showed protection from ultraviolet-induced redness. Such benefits for beta-carotene did not happen immediately and required an extensive, seven-week treatment period.

In a more recent double-blinded study with a group of 46 people, skin effects after 12 weeks of treatment with dietary supplements containing the carotenoids lutein (10 milligrams) and zeaxanthin (two milligrams) were measured. Similar to the results with beta-carotene and lycopene, treated participants showed protection from ultraviolet-induced redness compared to placebo-treated participants. There was a two-fold increase in minimal erythemal dose (MED), which is the amount of ultraviolet exposure needed to cause sunburn in people treated with the carotenoid supplements. Volunteers taking the carotenoid supplement also showed an increase in skin firmness and self-reported an improvement in overall skin tone. The levels of lutein and zeaxanthin used for this study are comparable to the amounts in single servings of dark green leafy vegetables, such as kale, spinach, turnip greens, collards, dandelion greens, and mustard greens.

Although the level of ultraviolet protection with carotenoid supplementation was not comparable to treatment with an SPF-containing topical product, these results demonstrate that achievable dietary changes can improve skin defenses and appearance.

TIMING IS EVERYTHING
What people eat is important, but when people eat affects their health as well. Upon waking up in the morning, people may well have gone as long as 12 hours without food or drink! Chances are, the body is dehydrated and starving for nutrients! A healthy breakfast with a balance of fat, protein, and complex carbohydrates will quickly provide energy and satisfy hunger. Lunch is a great time for feasting on fruit, salad, or vegetables. With busy schedules, it is easy to skip meals or end up eating a late dinner an hour before bedtime.

A heavy evening meal just prior to bedtime is more likely to disrupt sleep patterns. Lying down after a full meal can cause acidic stomach contents to irritate the esophagus and result in heartburn. Fatty foods are especially problematic; they take an extended time to digest and stay in the stomach longer. Caffeinated beverages, alcohol, dark chocolate, spicy foods, and acidic foods – tomatoes and citrus, for example – can also produce heartburn. The effects of inadequate sleep are always visible on the face. After all, "You look tired" is often a politely coded message for, "You look old." Avoiding heavy meals, alcohol, and acidic foods at least two or three hours before bed will help ensure uninterrupted "beauty" rest.

Decreasing food intake is an excellent way to lose weight and intermittent fasting has recently become a popular approach to a healthier lifestyle. There are various timetables for fasting: eating only during a set eight-hour period each day; fasting for 24 hours once or twice a week; or fasting for 24 hours once or twice a month.

From animal studies, it is clear that decreased caloric intake can improve longevity, decrease oxidative stress, and improve metabolism. Research has shown similar metabolic benefits for people. Although numerous followers have personal anecdotes about the skin benefits of periodic fasting, there has not been rigorous scientific testing to demonstrate measurable improvements in skin. For otherwise healthy adults, a meal pattern that incorporates fasting is easy enough to try for a period of time to see if it improves skin texture and/or appearance.

Skin health is a reflection of overall body health and a nutritionally sound diet, both of which are an important foundation for the best possible appearance. For some skin conditions, dietary changes can result in improvement, but set realistic expectations. The effect varies from person to person.

References
Burris, J., Rietker, W., and Woolf, K. (2013) Acne: The role of medical nutrition therapy. J Acad Nutr Diet 113:416-430.
Burris, J., Rietkerk, W. and Woolf, K. (2014) Relationships of self-reported dietary factors and perceived acne severity in a cohort of New York young adults. J. Acad Nutr Diet 114(3):384-92.
Harvie, M. and Howell A. (2017) Potential Benefits and Harms of Intermittent Energy Restriction and Intermittent Fasting Amongst Obese, Overweight and Normal Weight Subjects—A Narrative Review of Human and Animal Evidence. Behav. Sci 7(1): 4.
Juturu, V., Bowman, J.P., Deshpande, J. (2016) Overall skin tone and skin lightening-improving effects with oral supplementation of lutein and zeaxanthin isomers: a double-blind, placebo-controlled clinical trial. Clin Cosmetic & Invest Derm 9:325-332.
Kucharska, A., Szmurto, A. and Sinska, B. (2016) Significance of diet in treated and untreated acne vulgaris. Adv Dermatol Allergol 33(2):81-86.
LaRosa, C.L., Quach K.A., Koons, K., Kunselman, A.R., Zhu, J., Thiboutot, D.M. and Zaenglein, A.L. (2016) Consumption of dairy in teenagers with and without acne. J Acad Derm 75:318-322.
National Rosacea Society Website www.rosacea.org
Schagen, S.K., Zampeli, V.A., Makrantonaki, E. and Zouboulis, C. C. (2012) Discovering the Link Between Nutrition and Skin Aging. Dermato-Endocrinology 4(3):297-308.

Annette M. Tobia, Ph.D., is CEO and founder of Dynamis Skin Science, which offers the MEG 21 skin care product line. Tobia earned her Ph.D. from New York University and her law degree from Rutgers School of Law. She conducted postdoctoral research at Rocke-feller University.

Alice Marcy, Ph.D. is scientific operations officer at Dynamis Pharmaceuticals. Marcy earned her Ph.D. from Johns Hopkins University School of Medicine.