In the news: Supplements Stabilize Intermediate AMD? Glucosamine May Lower CVD Risk

Can Supplements Stabilize Intermediate AMD?

The authors of a multi-center controlled trial (1) report that supplementation of carotenoids, vitamins, minerals and omega-3 fatty acids over a 2-year period led to a meaningful stabilization of intermediate AMD.

The AREDS2 trial indicated that lutein and zeaxanthin are more appropriate than β-carotene in slowing progression of AMD. Despite experimental and epidemiologic evidence suggesting a protective role of the omega-3 fats, AREDS2 also found no additional benefit of these fatty acids when combined with an AREDS formula.

According to the new study’s authors, a consortium of Italian ophthalmologists, the role of supplemental omega-3 fats in dry AMD is still being debated (2) and additional clinical data are needed.

In this prospective, randomized double-blind study, 80 patients with intermediate AMD (AREDS Research Group classification) received placebo or a nutritional supplement (90 mg. vitamin C, 10 mg lutein, 2 mg zeaxanthin, 4 mg astaxanthin, 30 mg vitamin E, 22.5 mg zinc, 1 mg copper and 500 mg fish oil containing EPA 185 mg and DHA 140 mg).

AMD progression, the 1° endpoint, was assessed by retinography (digital fundus photographs), and BCVA was evaluated. An independent reading center judged all photographs taken during the trial. Progression of AMD was evaluated by retinography, by visual acuity both distance and near, and by a combination of all three parameters.

Seventy-four participants completed the study, 48 in the supplement arm and 26 in the placebo arm. Only 5 out of 74 (6.8%) patients showed AMD progression according to retinography: Three had an increase in atrophy while two developed wet AMD. Four out of these 5 patients were in the placebo arm (15.4%) and only one was in the supplement arm (2.1%). BCVA data alone did not differ between groups. No patients worsened in the supplement group when BCVA distance, BCVA near, and retinography were analyzed together. In contrast, 3 patients in the placebo arm worsened in all three parameters (p = 0.04 for between group comparison). The relatively short follow-up and small number of patients are limitations of this study.

However, the findings may warrant further study to evaluate the long-term effects of antioxidants / omega-3s in intermediate AMD.

Glucosamine Linked to Lower Risk of CVD

Supplemental glucosamine is widely used to relieve joint pain in osteoarthritis, with about 20% of US adults using it daily. Emerging evidence from animal and cross-sectional studies suggests that glucosamine may have a role in preventing CVD and reducing mortality, but prospective data is lacking.

A team from Harvard and Tulane Universities conducted a prospective study to assess the association of glucosamine use with the risk of CVD events (3). The study enrolled over 466,000 participants free of CVD at baseline who were followed for about 7 years. After adjusting for numerous factors, chronic glucosamine use was linked to a 15% lower risk of total CVD events, and a 22%, 18% and 9% lower risk of CVD death, coronary heart disease and stroke, respectively. Whether this commonly used supplement could help prevent CVD is an avenue of research worth exploring in clinical trials.

One caution about glucosamine use is worth noting. Several studies have raised the possibility that glucosamine use might increase IOP in those with glaucoma or ocular hypertension. One small retro-spective analysis (4) in 17 people with these conditions reported that IOP was about 18% higher while taking glucosamine compared to pre-use levels and returned to pre-use levels after glucosamine was discontinued. The results of two subsequent studies (5,6) suggest that for people without these conditions, and particularly younger people without these conditions, glucosamine appears to have little to no ocular effect.

References

1. Piatti A, et al. Effect of 2-year nutritional supple-mentation on progression of age-related macular degeneration. Eur J Ophthalmol. Epub March 18, 2019.
2. Souied EH, et al. Omega-3 Fatty Acids and Age-Related Macular Degeneration. Ophthalmic Res. 55:62-9, 2015.
3. Ma H, et al. Association of habitual glucosamine use with risk of cardiovascular disease: a prospective study in UK Biobank. BMJ. Epub May 14, 2019.
4. Murphy RK, et al. Oral glucosamine supplements as a possible ocular hypertensive agent. JAMA Ophthalmol. 131:955-7, 2013.
5. Esfandiari H, et al. Effect of glucosamine on intraocular pressure: a randomized clinical trial. Eye (Lond). 1:389-394, 2017.
6. Yuenyongviwat V, et al. Effect of glucosamine sulfate on intra-ocular pressure in patients with knee osteoarthritis: A prospective randomized controlled trial. J Fr Ophthalmol. Epub May 16, 2019.