Carotenoids are the yellow and orange pigments naturally found in many fruits and vegetables. Lutein is one of the most common carotenoids consumed in North American diets, along with α-carotene, β-carotene, β-cryptoxanthin, zeaxanthin and lycopene (2).
Lutein supplementation may help prevent age-related macular degeneration. Age-related macular degeneration is a leading cause of vision loss among people age 60 and older. This irreversible eye condition affects approximately 10 million Americans and is caused by damage to the macula — the central portion of the retina — that is responsible for all of our central vision, most of our color vision and the fine detail of what we see (3).
Researchers have found that increasing lutein and zeaxanthin intake — either through diet or supplements — may be a viable option for preventing this eye condition.
Lutein, zeaxanthin and meso-zeaxanthin are present in high concentrations in a healthy macula. They are collectively known as “macular pigment” due to them collecting in the macula. They are known to absorb damaging blue light and protect against light-induced oxidative damage, thought to play a role in macular degeneration.
Long-term exposure to blue light and oxidative damage may lead to pigment abnormalities in the macula, increasing the risk of age-related macular degeneration.
Sources of blue light include sunlight, fluorescent light, LED light, computer monitors, smart phones and tablet screens (4).
Studies show that the prevalence rate of macular degeneration in patients with low lutein intake is about twice as high as that in patients with high intake (5).
A two decade follow up on the long-term effects of lutein intake was published in a 2015 issue of JAMA Ophthalmology. A total of 63,443 women and 38,603 men were followed up, from 1984 until 2010.
It was found that higher intake of dietary lutein and zeaxanthin is associated with a long-term reduced risk of advanced macular degeneration (6).
Not all who increase their intake of lutein, however, see an increase in lutein levels in the macula. In one study, published in Investigative Ophthalmology & Visual Science, density was obtained within four weeks of dietary modification for most, but not all participants (7).
While evidence of lutein’s ability to reduce the progression of age-related macular eye disease is mounting, researchers still have many unanswered questions.
Lutein may help treat cataracts. It is estimated that 30.1 million Americans will have cataracts by 2020. Cataracts are the clouding of the lenses of the eyes that affect vision and is quite common in the elderly population (8).
A few studies show a modestly lower risk of having to have cataract surgery in those who eat higher amounts of lutein and zeaxanthin in their diets, versus those who have a higher intake of other carotenoids (alpha-carotene, beta-carotene, lycopene and beta-cryptoxanthin) or vitamin A (9).
Researchers note that broccoli and spinach are the foods consistently associated with a lower risk of cataracts.
In other studies, however, daily supplementation with lutein/zeaxanthin had no significant overall effect on the rates of cataract surgery or vision loss (10).
More studies are needed.
Lutein may help treat retinitis pigmentosa. Retinitis pigmentosa is a rare, genetic disorder that causes vision loss. The results of a study published in BMC Ophthalmology, suggest that lutein supplementation may preserve the vision in patients with this condition.
Thirty-four patients with retinitis pigmentosa were randomized to two groups. One group received lutein supplementation (10 mg/daily for 12 weeks followed by 30 mg/day) for the first 24 weeks and then placebo for the following 24 weeks; the second group received placebo (24 weeks) prior to lutein.
Results suggest that lutein supplementation improves visual field and also might improve visual acuity slightly (11).
Lutein helps prevent atherosclerosis. In vitro and mouse model findings support the theory that increased dietary intake of lutein helps prevent the development of early atherosclerosis — the hardening and narrowing of the arteries due to a buildup of fatty plaque.
In one study, researchers noted that pretreatment of cells with lutein prevented LDL-induced (a.k.a. “bad” cholesterol) migration in a dose-dependent manner (12). Over an 18-month period, participants with the highest serum lutein level had 80 percent less arterial wall thickening in comparison to those with the lowest serum lutein (13).
In addition, lutein supplementation reduced the size of atherosclerotic lesions in mice by 44 percent.
Lutein may decrease the risk of certain types of cancer. According to Memorial Sloan Kettering Cancer Center, increased consumption of lutein may decrease the risk of renal cell carcinoma, nonaggressive urothelial cell carcinoma and breast cancer (14).
Lutein has anti-inflammatory and antioxidant properties. Due to its antioxidant and anti-inflammatory potential, lutein intake may help treat diseases caused by oxidative stress and inflammation.
In an osteoarthritis study, lutein offered significant cytoprotection (cell protection from damage) by enhancing the antioxidant defense mechanisms and reducing oxidative stress.
In addition, lutein showed anti-inflammatory effects by downregulating inflammatory proteins and pro-inflammatory cytokines (15).
There are no known toxic effects of taking lutein. Very large doses, however, can cause a temporary yellow-orange skin discoloration, called carotenodermia.
Lutein can be easily incorporated into diets and is absorbed best with meals that are higher in fat. The best sources of lutein in foods are from egg yolks and spinach. Just one whole egg a day appears to increase plasma lutein by around 20-30 percent.
In one particular study, older adults eating one egg a day for five weeks saw an increase in serum lutein and zeaxanthin concentrations without elevating cholesterol concentrations (16).
Other sources include kale, winter squash, cruciferous vegetables, cabbage, green beans, yellow/orange fruits, mangoes, papayas, peaches and oranges.
When it comes to lutein supplementation, doses of up to 15 to 20mg a day appear to be safe (17).
Lutein is a carotenoid that is present in high concentrations in healthy eyes. Mounting evidence shows its ability to help treat and prevent certain eye conditions, especially age-related macular degeneration. Further studies are needed, however, due to inconsistent study outcomes.
Naturally found in egg yolks, spinach, kiwi, zucchini and different kinds of squash, lutein is also known for its antioxidant and anti-inflammatory properties.
It is also being studied for its ability to lower the risk of certain cancers and preventing atherosclerosis.