In the News: Healthy Habits & AMD, Diet & Kidney Function

Healthy Habits May Lower AMD Danger

Habits that help protect your heart – eating well, exercising and not smoking – are also good for your eyes according to new research from the Carotenoids in Age-Related Eye Disease Study (CAREDS) (1). The researchers concluded that adopting these lifestyle habits could reduce the number of people who develop advanced AMD, the leading cause of blindness among older Americans.

Of the 1,300 CAREDS participants who had provided detailed dietary and lifestyle data 6 years earlier, about 200 of them now showed signs of AMD – all but a few of them in the early stages of the disease.

Participants were divided into groups based on the quality of their diets. Points were awarded for eating vegetables, fruits, whole grains, and low-fat dairy, with points deducted for added sugar, salt and saturated fats. The group who ate the healthiest lowered their risk of AMD by 46%.

In terms of physical activity, the most active women were 54% less likely to develop the disease. Smoking was not a very strong risk factor when considered alone, but it did become important when grouped together with diet and exercise. Women who scored the highest on a combined healthy living index reduced their AMD risk by a striking 71%.

A healthy lifestyle could help prevent AMD by reducing blood pressure, inflammation and oxidative stress, according to the CAREDS researchers. They also point out that consuming more lutein and zeaxanthin favorably affects the eye’s macula, making it less vulnerable to oxidative damage.

Plant-Based Diet Best for Kidney Disease

People with chronic kidney disease are often advised to reduce their intake of phosphorus. That’s because impaired kidneys are less able to eliminate this mineral, causing blood levels to rise. Elevated blood phosphorus can lead to brittle bones, and is also linked to poorer outcomes for chronic kidney disease patients and those undergoing dialysis.

It can be challenging to restrict phosphorus intake since the mineral is found in so many foods and the dietary plan can be complex. However results from a new study (2) indicate that replacing meat and dairy sources of protein with plant-based alternatives can reduce blood phosphorus in kidney disease patients.

Telling patients just to use more vegetarian vs. meat products and less processed foods would be much easier than asking them to follow the complex renal plan, explained the study investigators.

This small trial compared the effects of a diet rich in plant protein to one higher in animal protein. Even though both diets provided equivalent amounts of protein and phosphorus, only the plant-based eating pattern lowered blood levels of the mineral. That’s probably due to the fact that most plant phosphorus is in the form of a compound (phytate) which isn’t absorbed.

The researchers were even more excited to find that the plant-based diet lowered levels of a phosphorus-regulating hormone (FGF-23). This hormone rises as kidney function declines, and is associated with increased mortality in kidney patients.

Can Diet Help Prevent Kidney Disease?

Findings from another new study suggest that a plant-based diet may also help prevent people from developing kidney disease in the first place (3).

In this study of over 3,100 women, those eating the most red and processed meats, saturated fats and added sugar had about twice the risk of developing changes that signal a decline in kidney function.

References

1. Mares JA, et al. Healthy Lifestyles Related to Subsequent Prevalence of Age-Related Macular Degeneration. Arch Ophthal Dec 13, 2010 [Epub ahead of print].
2. Moe SM, et al. Vegetarian compared with meat dietary protein source and phosphorus homeostasis in chronic kidney disease. Clin J Am Soc Nephrol 6:257-64, 2011.
3. Lin J, et al. Association of dietary patterns with albuminuria and kidney function decline in older white women. Am J kidney Dis 57:245-54, 2011.