RESEARCH UPDATE: A recent study investigates the effect on almond snacking on the skin’s resistance to harmful UVB light
A recent study2 showed that regular almond snacking may be one way to help your skin from within and support the other things you already do - like wearing sunscreen – to protect your skin from UVB rays.
In this study of 29 Asian women aged 18 to 45 years old, with skin types that ranged from “burns and does not tan easily” to “burns a little and tans easily,” technically classified as Fitzpatrick skin types II, III or IV, participants were randomly assigned to one of two groups for a 12-week period. The almond group ate 1.55 ounces (42 grams, 246 calories) of almonds daily, while the pretzel group ate 1.8 ounces (51 grams, 200 calories) of pretzels daily.
The researchers measured each person’s skin response to UVB rays – the type of rays known to cause sunburn - at the beginning and end of the study by quantifying their individual minimal erythema dose (MED). MED is the lowest dose of UVB light needed to cause slight skin reddening to a specific site on the skin. (In this case, inner-arm skin was chosen because it has little exposure to the sun.) Skin reddening is the first indication of skin photodamage, so increased MED indicates improved protection against (or resistance to) UVB photodamage.
Results:
- For the almond group, there was a significant increase in MED and in exposure time required to induce erythema at the final visit (12 weeks) compared to the start of the intervention (baseline) (p=.006). Further, the increase in MED in the almond group was statistically different compared to the pretzel group.
- For the women who consumed almonds, there was an increase in MED from 415±64 to 487±59 (18.7±19.2 %,p+0.006) from baseline to week 12 compared to women in the pretzel group from 415±67 to 421±67 (1.8±11.1%). The exposure time to reach minimal erythema (redness) was also increased significantly in the almond group from 160±23 to 187±25 (17.5±22.2%) compared to the pretzel group from 165±27 to 166±25 (1.7±14%) (p=0.026).
- At baseline, the groups had no significant differences of MED, which indicated the change in MED was due to the almond intervention. Increased MED and exposure mean that a higher dose of UVB light was required to induce erythema (redness) after 12-weeks, compared to the pretzel group.
- There were no significant differences between the two groups in their ratings of erythema or Allergan Skin Roughness by dermatologists’ assessment.
- There were no significant differences in melanin index, sebum hydration or erythema by cutometer reading.
- The mechanism for the improvement in UV resistance with the almond intervention is currently unknown. The researchers speculate that the nutrients in almonds (mono- and polyunsaturated fatty acids, vitamin E, quercetin (a flavonoid), and other phenolic and polyphenolic compounds, may improve the antioxidant and anti-inflammatory capacity of human skin, which could be responsible for the increased photoprotection against UVB light.
Study Limitations: A smaller study population was included than originally planned, due to the exclusion of those participants found to be UVB resistant at the dose and exposure time selected. This study did not investigate the effect of sunlight exposure in general nor UVA exposure; findings are limited to protection against UVB radiation. This study also investigated a younger population. Further research is needed to investigate the effects of almond consumption for older subjects with moderate-to-severe photoaged skin and for other Fitzpatrick skin types.
Conclusion: A daily snack of almonds (1.5 ounces or 42 grams) improved UVB resistance in young Asian women who consumed almonds for 12 weeks. The results suggest that including almonds in the diet may help support the skin’s internal defenses against UVB light.
