Turmeric & Arteries; Lutein in early AMD; Calcium & CVD

Curry Spice May Boost Blood Vessel Health

Curcumin is the yellow-orange pigment found in turmeric, the spice used in Indian curry dishes. Researchers have been interested in curcumin for some time, and the compound has shown some preliminary promise in addressing colon polyps and reducing inflammation in arthritis.

The new study (1) looked at the effects of curcumin on the ability of blood vessels to dilate when needed. A key step in the development of atherosclerosis or “hardening” of the arteries occurs when the lining of the vessels (called the endothelium) does not function properly to help regulate blood flow.

Researchers assigned postmenopausal women to one of three groups: one received 25 mg of curcumin daily, another undertook moderate aerobic exercise training, and a third group served as a control.

After 2 months, both the curcumin and exercise groups had significant – and equal – improvements in flow-mediated dilation (FMD). FMD is a test of endothelial function and the ability of vessels to dilate when blood flow increases. In contrast, no improvements in FMD were observed in the control group. Though the study was small, the results indicate that this spice has good heart-health potential.

Lutein May Benefit Visual Acuity in Early AMD

Lutein and zeaxanthin are part of the eye’s macula, the functional center of the retina. The macula provides us with sharp central vision and it contains photoreceptors called cones that provide color vision. Lutein and zeaxanthin, known as macular pigment, play a critical role in protecting the macula from harmful blue light.

The density of macular pigment has been shown to decline with age, and having low macular pigment density is considered a risk factor for AMD. Lutein and zeaxanthin, in fact, are being tested in the 2nd Age-related Eye Disease Study (AREDS2), to see whether they can slow the progression of AMD in people who already have intermediate to advanced stages of the disease. While AREDS2 isn’t studying people with early signs of AMD, new research from the UK sheds some light on the effects of lutein in early-stage AMD.

In this study (2), patients received either 10 mg of lutein or a placebo for 12 months. Macular pigment density increased significantly in the lutein group. Visual acuity, a measure of the sharpness of vision, was unchanged in the lutein group as a whole, while it deteriorated in the placebo takers.

Further analysis showed that lutein did improve visual acuity in those who had poor clarity of vision at the study’s start. The investigators suggest that lutein supplementation may slow the progress of AMD in some patients in the early stages of the disease.

Can Too Much Calcium Cause Heart Disease?

Several studies have recently reported a link between high intake of calcium from diet and supplements and a higher risk of heart disease. The theory is that excess calcium can be deposited in arteries, making them stiff and leading to heart conditions and stroke. A newly published study (3), however, suggests that concern about calcium supplementation doesn’t seem to be warranted.

Investigators performed CT scans on participants in the Framingham Offspring Study four years after collecting information about their diet and supplement use. The CT scans found no association between even the highest calcium intake (from food and supplements combined) and coronary artery calcification.

Though these findings are reassuring, keep in mind that taking higher-than-recommended amounts of calcium offers no benefit. A new analysis (4) of the large Women’s Health Initiative found that 1,000 mg of calcium (+ 400 IU vitamin D) daily substantially lowered the risk of hip fracture in postmenopausal women with no risk of cardiovascular harm.

References

1. Akazawa N et al. Curcumin ingestion and exercise training improve vascular endothelial function in postmenopausal women. Nutr Res 32:795-9, 2012.
2. Murray IJ et al. Lutein supplementation over a one-year period in early AMD might have a mild beneficial effect on visual acuity: the CLEAR study. Invest Ophthalmol Vis Sci 11:1781-8, 2013.
3. Samelson EJ et al. Calcium intake is not associated with increased coronary artery calcification: the Framingham Study. Am J Clin Nutr 96:1274-80, 2012.
4. Prentice RL et al. Health risks and benefits from calcium and vitamin D supplementation. Osteo Inter 24:567-80, 2013.