In the news:Lutein Linked to Memory Performance; Nutrition Plays a Role in Skin Health

Blood Lutein Levels Linked to Memory Performance in Overweight & Obese.

The carotenoid lutein is deposited in nerve tissue and a number of regions in the brain, as well is in the eye’s macula. Research has been ongoing to better under-stand the relationship between lutein and various aspects of memory.

The current study (1), conducted by a team of neuro-scientists and nutritional researchers at the University of Illinois at Urbana-Champaign, focused on memory functions associated with the brain’s hippocampus. The hippocampus is a horseshoe shaped area in the middle temporal lobe responsible for remembering the location of objects and people, emotional responses, and assisting in the storage of long-term memories.

The research team chose to study overweight and obese participants since previous reports have linked excess fat to poorer cognitive function and brain structure, and the hippocampus is thought to be affected by obesity. Additionally, obese individuals often have lower tissue concentrations of lutein.

The diets of 94 healthy but overweight or obese adults were assessed for intake of various carotenoids (e.g beta carotene, beta cryptoxanthin), and serum levels of those carotenoids as measured, as was macular pigment density.

The participants underwent standard tests (spatial reconstruction tasks) of relational memory, which is a hippocampal-dependent process that allows us to put a name to a face or retell the story of a trip in any order we choose, for example.

After adjusting for other factors such as age, gender and body mass index, only serum lutein levels were positively linked to better performance on relational memory tasks. Other carotenoids were not, nor was macular pigment density.

According to the authors, “findings from this study indicate that among the carotenoids evaluated, lutein may play an important role in hippocampal function among adults who are overweight or obese.”

Diet, Nutrients and Skin Health

Growing evidence indicates that diet plays a role in overall skin health as well as the development of several common skin diseases, according to a new review in the dermatology journal Cutis (2).

Preliminary evidence raises promise for the Mediterranean diet in psoriasis, an autoimmune and chronic inflammatory condition. In a study that examined the association between adherence to a Mediterranean diet and the onset and/or severity of psoriasis (3), participants sticking most closely to the Med diet were significantly less likely to have severe psoriasis. Those with severe disease displayed low adherence to the diet. The reviewers also point to studies suggesting a higher rate of vitamin D deficiency in patients with psoriasis, but studies showing that supplemental vitamin D is of benefit in the condition are lacking to date.

Several studies support a role for a low glycemic index diet in reducing acne lesions and improving acne vulgaris overall. A low glycemic index diet is one rich in fruits, vegetables, unprocessed grains and ample fiber. The reviewers also discussed a randomized trial in which both omega-3 fatty acids from fish and gamma linolenic acid reduced acne lesions (both inflammatory and non-inflammatory lesions) and reduced acne severity in acne vulgaris patients.

The reviewers touched on other emerging research investigating the role of gut microflora in various conditions. They cited a study in which a supplemental prebiotic (food for gut bacteria, in this case oligo-saccharides) were given to children at risk of developing atopic dermatitis. At 6-month follow-up, 24 participants in the placebo group had developed atopic dermatitis compared to only 10 in the prebiotic group.

References

1. Cannavale CN, et al. Serum lutein is related to relational memory performance. Nutrients. 11:768, 2019.
2. Soliman YS, et al. The role of diet in preventing photo-aging and treating common skin conditions. Cutis. 103:153-6, 2019.
3. Phan C, et al. Association between Mediterranean anti-inflammatory dietary profile and severity of psoriasis: results from the NutriNet-Santé cohort. JAMA Dermatol. 154:1017-24, 2018.