Gut Bacteria (2016) & Advanced Macular Degeneration

Learn more about macular degeneration.

2017
Microbiota and High-Glycemia Diet

Researchers have noted in the past that the inability of the body to properly process sugar, leading to advanced glycation (bonding of sugar molecules with proteins and other molecules), and contributes to development of macular degeneration.

Researchers analyzing the process of glycation, resulting increased inflammation and development of macular degeneration found that high-glycemia diets contribute to AMD risk and low-glycemic diets reduce the risk and may even stop or reverse AMD development.

The researchers concluded that the health of gut microbiota was a factor in the ability of the body to process sugars and that this ability was hampered in a high-glycemia diet.

Researchers: S. Rowan, S. Jiang, et al
Published: Involvement of a gut-retina axis in protection against dietary glycemia-induced age-related macular degeneration, Proceedings of the National Academy of Science, USA, May, 2017.

2016
Microbiota & High Fat Diet

The risk of developing advanced macular degeneration (choroidal neovascularization (CNV)) is greatly increased, especially for men, in the presence of obesity. Being overweight is the second most severe risk factor after smoking. In a study of over 21,000 people it was found that each increase in .1 in waist/hip ratio was associated with a 13% increase in the risk of developing macular degeneration.¹

However the mechanisms that cause this association are not strongly understood so researchers decided to investigate. Our ability to digest food and gain nutritional benefit from the food we eat depends on the ability of our digestive system to break down the food into nutrients. This takes place in the large and small intestines and rests on the health of the microbacterial community that lives in our gut.

But in the presence of fat molecules, the process is slowed or inhibited. People who are obese tend to have high-fat diets, and this inhibition on our healthy gut microbiota restricts the delivery of nutrients to the body and to the eyes and becomes a risk factor for AMD. Imbalances in the gut microbiota influence not only digestion but metabolism, toxins in bacterial cells, and the immune system's response.

Researchers find that gut imbalanced or maladapted gut microbiota increases the permeability of the gut resulting in chronic inflammation. And we know from other research² that increased inflammation is present in cases of advanced macular degeneration.

In this study the scientists started by looking at the link between high fat diets and CNV. In lab animals they found a clear association between excessive weight gain and CNV development.

Next they disassociated the weight gain factor from the imbalanced gut microbiota community by feeding normal weight animals with antibiotics to damage the gut microbiota. They examined the gut flora profile to establish that the microbiota had been negatively impacted.

They found that certain large molecules (mononuclear phagocytes that are known to contribute to CNV were increased in the imbalanced digestive systems of the mice, and that they promote inflammation.

Finally, they were able to determine that the high fat diets increase advanced macular degeneration (CNV) because the resulting imbalanced gut microbiota aggravated inflammation which in turn aggravated CNV.

Researchers: E.M. Andriessen, A.M. Wilson, et al,
Published: Gut microbiota influences pathological angiogenesis in obesity-driven choroidal neovascularization, EMBO Molecular Medicine, December, 2016.

Footnotes

1. M. Adams, J. Simpson, et al., Abdominal obesity and age‐related macular degeneration, American Journal of Epidemiology, 2011.
2. Vinod P. Mitta, MD, MPH; et al, C-Reactive Protein and the Incidence of Macular Degeneration, JAMA Ophthalmology, 2013