The study was funded by the Almond Board of California. A larger and longer-term follow-up study is underway.
In this 16-week randomized controlled trial, 28 healthy postmenopausal women with Fitzpatrick skin type 1 or 2 (characterized by increased tendency to burn with sun exposure) were randomly assigned to one of two groups. In the intervention group, women ate almonds as a snack, which accounted for 20% of their total daily calorie intake, or 340 calories per day on average (about 2 one-ounce servings). The control group ate a nut-free snack that also accounted for 20% of calories: a cereal bar, granola bar or pretzels. Aside from these snacks, study participants ate their regular diets and did not eat any nuts or nut-containing products.
Skin assessments were made at the start of the study, and again at 4 weeks, 8 weeks, 12 weeks and 16 weeks. At each visit, facial wrinkles were assessed using high-resolution facial imaging and validated 3-D facial modeling and measurement. "These high resolution cameras allow for 3-D reconstruction of any wrinkles so that they can be mapped for their key characteristics of width and severity. The severity score is a calculation of the depth and length of a wrinkle," said Raja Sivamani, MD MS AP, integrative dermatologist and lead researcher on the study. Skin barrier function was also assessed, by measuring sebum production and transepidermal water loss (TEWL). Skin barrier function examines the strength of the skin barrier and how well it protects skin from moisture loss (TEWL) and from harmful irritants coming from the environment.
By the end of the study at 16 weeks, photographic image analysis showed statistically significant improvements for participants in the almond snack group compared to the control group (P<0.02):
- Wrinkle width decreased by 10%
- Wrinkle severity decreased by 9%
- There were no significant changes in skin barrier function between groups.
"Food as a means of promoting skin health—the ‘health from the inside out’ idea—is of growing interest to those looking for options for healthy aging," said Sivamani. "It's also a growing area of scientific research. Almonds are a rich source of antioxidant vitamin E and deliver essential fatty acids and polyphenols. They're a smart choice for overall good nutrition. And, as seen in this study, almonds may hold promise as a food to include as part of a healthy aging diet, especially for post-menopausal women."
Aging is a long-lasting process so the findings from this 16-week study may be difficult to reproduce and generalize to extended periods of time. Skin aging is also multi-factorial in nature and although certain groups were excluded (i.e., those with a smoking history), there is variance in aging confounders, such as frequency of UV light exposure and emotional stress, which were outside the scope of the study. This study was limited to cosmetic evaluation, as no measurements were made regarding collagen production. Study did not evaluate disease or younger subjects, so results are limited to otherwise healthy post-menopausal females. In addition, this was a pilot study with a limited number of participants. Future studies should expand to a larger recruitment pool.
Results of this pilot study suggest that daily consumption of almonds may play a role in reducing wrinkle severity in post-menopausal women. The outcomes warrant future studies with expanded population groups and additional evaluations for signs of skin aging, researchers said.