In the news: Higher B1 Intake Lowers Late AMD Risk? Stress-induced inflammation Drives MetS

Higher B1 Intake May Lower Late AMD Risk

According to growing observational study findings, increased intakes of various vitamins and minerals are related to slower development of age-related macular degeneration (AMD) or to the delay of its progression to intermediate or late stages.

One nutrient of interest is vitamin B1 (thiamine), which is an important cofactor for a wide variety of enzymes that are engaged in important metabolic processes, especially in the metabolism of carbohydrates and amino acids.

There is mounting evidence that thiamin also has antioxidant properties, and that it may help protect retinal tissues from radical oxygen species (ROS). With its strong oxygen metabolism, retinal tissue produces abundant ROS, leaving it vulnerable to oxidative injury. It’s established that oxidative stress is a major contributing factor to AMD pathogenesis.

Thiamine’s potential relevance to ocular health led researchers to assess the association between the vitamin and the prevalence of late AMD in a representative US sample – participants in the National Health and Nutrition Examination Survey (NHANES).

This cross-sectional study(1) included over 5,000 individuals aged 40 years or older with dietary intake data. Fundus photographs from NHANES were used to classify early and advanced AMD.

After fully adjusting for numerous potential confounding variables, the investigators found an inverse association between B1 intake and late AMD. Compared with a lower intake, higher thiamine consumption correlated with a 38% lower risk for late AMD ((OR = 0.62). No link between thiamine and early AMD was observed.

The investigators concluded that further randomized clinical trials among multiple centers are warranted to investigate the longitudinal and causal relationship between vitamin B1 intake and late AMD.

How Stress May Drive Metabolic Syndrome

According to the findings of Ohio State researchers(2), stress may contribute to a state of chronic, low-grade inflammation that leads to metabolic dysregulation. The investigators suggest that affordable and relatively easy stress management techniques may be one means of improving the health of those with metabolic syndrome (MetS) – a condition affecting an estimated 1 in 3 US adults.

Metabolic syndrome, also referred to as insulin resistance syndrome, is defined as having at least three of five risk factors for heart disease, type 2 diabetes, and stroke. The risk factors include excess abdominal fat, hypertension, low HDL, high fasting blood glucose, and elevated triglycerides.

A link between stress and health is established, but few studies have looked specifically at the involvement of inflammation in the connection of stress to metabolic syndrome.

The study, supported by the National Institutes of Aging, used data from 648 participants in the Midlife in the US Study which provided measures of perceived stress, inflammatory biomarkers C-reactive protein, interleukin-6, E-selectin, fibrinogen, intracellular adhesion molecule-1 and metabolic health markers.

Statistical modeling demonstrated that stress was linked to metabolic dysregulation through inflammation (p < .001). Inflammation explained a large proportion – about 61% – of that connection.

These results suggest that inflammatory biomarkers are a viable explanatory pathway for the relationship between perceived stress and metabolic health consequences, according to the authors. Reducing stress may be one option to mitigate inflammatory health risks.

References

1. Zheng Q, et al. Association between dietary consumption of vitamin B1 and advanced AMD: a cross-sectional observational study in NHANES 2005-2008. Ophthalmic Res. ePub ahead of print, Nov. 3, 2023.
2. Savana M, et al. Inflammatory biomarkers link perceived stress with metabolic dysregulation. Brain Behav Immun Health. 34:100696, 2023.