FROM THE ACADEMY Question of the Month
Is There Research to Support a Specific Diet for Psoriasis?
A
PERSON’S SKIN CONSTANTLY sheds dead cells and produces new ones in a process called cell turnover. Normally, it takes about a month for new cells that grow deep in the skin to rise to the surface, but in psoriasis this process is accelerated and new cells rise from below the skin surface in a matter of days.1 Overgrowths of cells accumulate on the skin surface resulting in red, flaky, crusty patches covered with silvery lesions. Despite the fact that it is not a contagious disorder and the patches are not infectious, people with the condition can suffer from social exclusion. According to the National Psoriasis Foundation (NPF), psoriasis is the most prevalent autoimmune disease in the United States, and studies indicate as many as 7.5 million Americans suffer from it.2 As is often the case in patients with chronic diseases, people with psoriasis turn to diet in hopes of a positive impact on their condition. A poster session presented at the 2011 Food & Nutrition Conference & Expo in San Diego, CA, summarized a literature search on Medline (1950 to January 2011) for studies testing the effectiveness of any diets or dietary supplements in reducing psoriasis symptoms.3 Approximately 228 articles were found, including articles on the impact of obesity on psoriasis and the effectiveness of a gluten-free diet on psoriasis, among other factors. The meeting abstract for the poster session noted some evidence supportive of a low-calorie/low-energy diet. In 2013, a small clinical trial based in Denmark
This article was written by Eleese Cunningham, RDN, of the Academy of Nutrition and Dietetics’ Knowledge Center Team, Chicago, IL. Academy members can contact the Knowledge Center by sending an e-mail to [email protected]. http://dx.doi.org/10.1016/j.jand.2014.01.003
508
reported what they believed to be the first results of a study on the effects of weight loss using the severity of psoriasis as a primary endpoint. The researchers found that obese patients with psoriasis who lost weight through a low-calorie diet experienced a significant improvement in their quality of life compared with obese psoriasis patients who didn’t lose weight. In the randomized clinical trial, 27 patients were assigned to an intervention group that followed a low-calorie diet, and 26 patients were assigned to a control group that continued to eat ordinary healthy foods. The participants met every 2 weeks for a total of eight group sessions led by the study dietitian. The patients on a low-calorie diet ended up losing nearly 34 lb in 16 weeks, and reported improvements in both their psoriasis symptoms and their overall quality of life.3 There are data that suggest that following a gluten-free diet may ameliorate symptoms in individuals with chronic autoimmune disease conditions such as psoriasis.4 However, the NPF states that the jury is still out on this topic. In some cases, eliminating gluten does seem to help reduce psoriasis. In a smaller number of cases, eliminating gluten can lead to dramatic improvements.5 If celiac disease or gluten sensitivity is suspected, a registered dietitian nutritionist should coordinate care with a physician to evaluate the patient for either of these conditions in order to determine the appropriateness of a gluten-free diet. For the client with psoriasis who does not also have celiac disease or gluten sensitivity, it is not advised to follow a gluten-free diet. The Incident Health Outcomes and Psoriasis Events (iHOPE) Study, which examined the prevalence of major medical comorbidity in patients with mild, moderate, or severe psoriasis classified objectively based on body surface area involvement compared
JOURNAL OF THE ACADEMY OF NUTRITION AND DIETETICS
with that in patients without psoriasis, found a definite link between the severity of a person’s psoriasis and the odds that person may develop several other diseases,6 including:
chronic pulmonary disease; diabetes; mild liver disease; myocardial infarction and peripheral vascular disease (cardiovascular disease); peptic ulcer disease; renal disease; and other rheumatological diseases.6,7
According to Mark Lebwohl, MD, a dermatologist commenting on the iHOPE study, “Many of the other diseases linked to psoriasis are linked to obesity, and several of the diseases indicated in the study are already linked to obesity, too, like diabetes and hypertension. Exercising, eating right, quitting smoking, and treating psoriasis can help prevent comorbidities.”7
References 1.
MedlinePlus. Psoriasis. http://www.nlm.nih. gov/medlineplus/psoriasis.html. Accessed December 23, 2013.
2.
National Psoriasis Foundation. Frequently Asked Questions. http://www.psoriasis.org/ page.aspx?pid¼375. Accessed December 23, 2013.
3.
Brown AC, Shankar P. Psoriasis, diet, and dietary supplements—A review [abstract]. J Am Diet Assoc. 2011;111 (suppl 2):A33.
4.
Jensen P, Zachariae C, Christensen R, et al. Effect of weight loss on the severity of psoriasis: A randomized clinical study. JAMA Dermatol. 2013;149(7):795-801.
5.
Gaesser GA, Angadi SS. Gluten-free diet: Imprudent dietary advice for the general population? J Acad Nutr Diet. 2012;112(9): 1330-1333.
6.
Yeung H, Takeshita J, Mehta NN, et al. Psoriasis severity and the prevalence of major medical comorbidity: A population-based study. JAMA Dermatol. 2013;149(10): 1173-1179.
7.
National Psoriasis Foundation. Study: Risk of serious medical events increases with psoriasis severity. http://www.psoriasis.org/ news/stories/2013/08/08/risk-of-seriousmedical-events-increases-with-psoriasisseverity. Accessed December 23, 2013.
ª 2014 by the Academy of Nutrition and Dietetics.
Is There Research to Support a Specific Diet for Psoriasis?
A
PERSON’S SKIN CONSTANTLY sheds dead cells and produces new ones in a process called cell turnover. Normally, it takes about a month for new cells that grow deep in the skin to rise to the surface, but in psoriasis this process is accelerated and new cells rise from below the skin surface in a matter of days.1 Overgrowths of cells accumulate on the skin surface resulting in red, flaky, crusty patches covered with silvery lesions. Despite the fact that it is not a contagious disorder and the patches are not infectious, people with the condition can suffer from social exclusion. According to the National Psoriasis Foundation (NPF), psoriasis is the most prevalent autoimmune disease in the United States, and studies indicate as many as 7.5 million Americans suffer from it.2 As is often the case in patients with chronic diseases, people with psoriasis turn to diet in hopes of a positive impact on their condition. A poster session presented at the 2011 Food & Nutrition Conference & Expo in San Diego, CA, summarized a literature search on Medline (1950 to January 2011) for studies testing the effectiveness of any diets or dietary supplements in reducing psoriasis symptoms.3 Approximately 228 articles were found, including articles on the impact of obesity on psoriasis and the effectiveness of a gluten-free diet on psoriasis, among other factors. The meeting abstract for the poster session noted some evidence supportive of a low-calorie/low-energy diet. In 2013, a small clinical trial based in Denmark
This article was written by Eleese Cunningham, RDN, of the Academy of Nutrition and Dietetics’ Knowledge Center Team, Chicago, IL. Academy members can contact the Knowledge Center by sending an e-mail to [email protected]. http://dx.doi.org/10.1016/j.jand.2014.01.003
508
reported what they believed to be the first results of a study on the effects of weight loss using the severity of psoriasis as a primary endpoint. The researchers found that obese patients with psoriasis who lost weight through a low-calorie diet experienced a significant improvement in their quality of life compared with obese psoriasis patients who didn’t lose weight. In the randomized clinical trial, 27 patients were assigned to an intervention group that followed a low-calorie diet, and 26 patients were assigned to a control group that continued to eat ordinary healthy foods. The participants met every 2 weeks for a total of eight group sessions led by the study dietitian. The patients on a low-calorie diet ended up losing nearly 34 lb in 16 weeks, and reported improvements in both their psoriasis symptoms and their overall quality of life.3 There are data that suggest that following a gluten-free diet may ameliorate symptoms in individuals with chronic autoimmune disease conditions such as psoriasis.4 However, the NPF states that the jury is still out on this topic. In some cases, eliminating gluten does seem to help reduce psoriasis. In a smaller number of cases, eliminating gluten can lead to dramatic improvements.5 If celiac disease or gluten sensitivity is suspected, a registered dietitian nutritionist should coordinate care with a physician to evaluate the patient for either of these conditions in order to determine the appropriateness of a gluten-free diet. For the client with psoriasis who does not also have celiac disease or gluten sensitivity, it is not advised to follow a gluten-free diet. The Incident Health Outcomes and Psoriasis Events (iHOPE) Study, which examined the prevalence of major medical comorbidity in patients with mild, moderate, or severe psoriasis classified objectively based on body surface area involvement compared
JOURNAL OF THE ACADEMY OF NUTRITION AND DIETETICS
with that in patients without psoriasis, found a definite link between the severity of a person’s psoriasis and the odds that person may develop several other diseases,6 including:
chronic pulmonary disease; diabetes; mild liver disease; myocardial infarction and peripheral vascular disease (cardiovascular disease); peptic ulcer disease; renal disease; and other rheumatological diseases.6,7
According to Mark Lebwohl, MD, a dermatologist commenting on the iHOPE study, “Many of the other diseases linked to psoriasis are linked to obesity, and several of the diseases indicated in the study are already linked to obesity, too, like diabetes and hypertension. Exercising, eating right, quitting smoking, and treating psoriasis can help prevent comorbidities.”7
References 1.
MedlinePlus. Psoriasis. http://www.nlm.nih. gov/medlineplus/psoriasis.html. Accessed December 23, 2013.
2.
National Psoriasis Foundation. Frequently Asked Questions. http://www.psoriasis.org/ page.aspx?pid¼375. Accessed December 23, 2013.
3.
Brown AC, Shankar P. Psoriasis, diet, and dietary supplements—A review [abstract]. J Am Diet Assoc. 2011;111 (suppl 2):A33.
4.
Jensen P, Zachariae C, Christensen R, et al. Effect of weight loss on the severity of psoriasis: A randomized clinical study. JAMA Dermatol. 2013;149(7):795-801.
5.
Gaesser GA, Angadi SS. Gluten-free diet: Imprudent dietary advice for the general population? J Acad Nutr Diet. 2012;112(9): 1330-1333.
6.
Yeung H, Takeshita J, Mehta NN, et al. Psoriasis severity and the prevalence of major medical comorbidity: A population-based study. JAMA Dermatol. 2013;149(10): 1173-1179.
7.
National Psoriasis Foundation. Study: Risk of serious medical events increases with psoriasis severity. http://www.psoriasis.org/ news/stories/2013/08/08/risk-of-seriousmedical-events-increases-with-psoriasisseverity. Accessed December 23, 2013.
ª 2014 by the Academy of Nutrition and Dietetics.
