For our recent Eye Health Special Edition, we discussed the pursuit of a DRI for lutein with leading industry figures, all of whom agreed that achieving this would be “a long and arduous process”, which could require more than five years to complete.
Dietary Reference Intakes (DRIs) are a set of four nutrient reference values for healthy populations. They include the Recommended Daily Allowance (RDA), Adequate Intake (AI), Estimated Average Requirement (EAR), and Tolerable Upper Intake Level (UL).
“I think academia and industry is enthused about DRIs for lutein, but we’re a long way away,” said Elizabeth Johnson, PhD, Scientist I in the Antioxidants Laboratory in the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.
Dr Johnson, who works at the cutting edge of lutein research, said that any progress on a DRI would require someone from the FDA getting on board, or as she puts it, “a cheerleader on the inside. Someone to push it internally and we don’t have that”.
“But I think it’s important that it happens. Lutein is out there and people know about it. I think it would be a nice case scenario for bioactives because of the science behind lutein.”
All eyes on lutein
The link between lutein and eye health was first reported in 1994 by Dr Johanna Seddon and her co-workers at Harvard University, who found a link between the intake of carotenoid-rich food, particularly dark green leafy vegetables like spinach, and a significant reduction in age-related macular degeneration (AMD) (
The macula is a yellow spot of about five millimeters diameter on the retina. As we age, levels of the pigments in the macula decrease naturally, thereby increasing the risk of AMD. The yellow color is due to the content of the carotenoids lutein and zeaxanthin.
JAMA, Vol. 272, pp. 1413-1420). The burden of AMD falls on 25 to 30 million people worldwide, according to AMD Alliance International.
Research dollars have flowed into research (both public and private) exploring lutein and zeaxanthin for eye health, with many positive studies boosting the lutein/zeaxanthin market, worth approximately $145 million globally. In the US it is estimated to be between $90 and 100 million.
“Lutein is not an essential nutrient,” said Dr Johnson, “meaning you don’t see a specific disease when it’s removed from the diet, and so for this bioactive we need a different framework for DRIs.
“Ideally we need to do something,” she added, “because most everyone is getting less than two milligrams per day. The level to give a protective reduction in the risk of AMD is about six milligrams per day, so there’s a gap. People really need to have the recommendation to meet those needs. And this has implications for meals on wheels, for school lunch programs, and so on.”
New criteria for DRIs for bioactives
At Experimental Biology earlier this year Dr Johnson discussed the criteria needed for bioactives to get recommendations, based on the nine criteria presented by Joanne Lupton et al. in the European Journal of Nutrition (Vol. 53 Suppl 1, pp. 1-9, doi: 10.1007/s00394-014-0666-3), which are listed as:
1. A deﬁnition of the substance which is commonly accepted
2. Preferably backed up by a multi-center analysis such as an AOAC method
3. Database of the amount of the bioactive in foods
4. Prospective cohort studies
5. Clinical trials on digestion, absorption, activation, transport, excretion of the substance
6. Clinical trials on efﬁcacy and dose–response data
7. Safety data at the level of intake that might be anticipated
8. Systematic Reviews and/or meta analyses showing efﬁcacy
9. A plausible biological explanation for efﬁcacy