The recommendations for a healthy diet are the same for men and women. Eat fruits and vegetables, whole grains, healthy proteins and limit sodium, added sugars and saturated fat. When it comes to individual nutrients, however, daily needs are not always similar due to differences in sex hormones. Menstruating women need more iron than men, for example. And with the loss of estrogen that occurs with menopause, a woman’s daily calcium requirement increases to help protect against osteoporosis. According to researchers from the University of Georgia, there is another dietary component that women should be cautious about: carotenoids. This is especially true when it comes to protecting against cognitive decline and vision loss. Here’s why and how to consume more of them.
Gender differences in eye and brain health
While females tend to live longer than males, they are more vulnerable to diseases and conditions that, while not always life-threatening, are debilitating. Cataracts, macular degeneration and dementia, for example, affect women more often and earlier than men. The research review, published June 11 in the journal Nutritional Neuroscience, reports that women account for 70 percent of all dementia cases, primarily Alzheimer’s dementia and age-related macular degeneration. Reasons include hormonal differences, genetic variations, and/or differences in the generation of inflammation and oxidative stress. Oxidative stress occurs in the body when there is an imbalance between free radicals and antioxidants. When left unchecked, free radicals can damage cells and tissues.
Carotenoids: focus on lutein
In the new review, researchers argue that higher rates of neurodegenerative diseases in women could be reduced by eating a diet rich in carotenoids, phytochemicals that have powerful antioxidant and anti-inflammatory effects. Watermelon is a source of lycopene.Getty Images/iStockphoto Carotenoids in our diet include beta-carotene (e.g. carrots, sweet potato, mango, spinach), lutein and zeaxanthin (e.g. spinach, cabbage, chard), lycopene (e.g. tomato sauce, tomato juice, watermelon) and β-cryptoxanthin (eg pumpkin, papaya, red pepper). Lutein and zeaxanthin are the only carotenoids found in the eye. they are concentrated in the macula, the central part of the retina that controls fine detailed vision. Here they protect the eye tissues from the production of free radicals caused by light. Lutein and zeaxanthin are also the main carotenoids found in the brain. Many studies have linked higher intakes of lutein and zeaxanthin to a lower risk of macular degeneration and cataracts. Studies conducted in children, young adults, older adults, and adults with cognitive impairments suggest that increased intake of lutein and zeaxanthin improves brain function.
What is the recommended daily intake of lutein?
Unlike vitamins and minerals, there are no official recommended daily intakes for phytochemicals, including carotenoids. Evidence from observational research, however, suggests that a daily intake of 3 to 5 mg of lutein and zeaxanthin protects against early, intermediate, and advanced age-related macular degeneration. A 2020 study published in the American Journal of Clinical Nutrition found that a daily intake of 25 mg of total carotenoids was associated with a lower risk of Alzheimer’s disease in older adults. High intakes of lutein and zeaxanthin were particularly protective. Interestingly, the latest research review shows that women need more carotenoids than men to protect against disease. One reason has to do with how they are stored in the body. Carotenoids, which are fat-soluble, are stored in adipose tissue. Females have, on average, more body fat than males. Research has shown that, despite similar intakes and blood levels of lutein and zeaxanthin, females have higher levels of these in their adipose tissue than males. These stocks are useful during pregnancy and breastfeeding. But, according to the researchers, it also means that less lutein and zeaxanthin is available for the eyes and brain, putting women at greater risk for degenerative problems later on. They conclude that “given the high potential for help and low potential for harm, targeting women’s intake of lutein and zeaxanthin is a wise strategy.”
What are the best food sources for lutein?
Excellent sources of lutein and zeaxanthin are cooked leafy vegetables such as spinach (15 mg per half cup), kale (12.5 mg), Swiss chard (9.5 mg), collard greens (9 mg), dandelion (5 mg) and mustard greens (4 mg). These vegetables also provide a decent amount of beta-carotene. victoriya89/Getty Images/iStockphoto Other sources of lutein and zeaxanthin are summer and winter squash, peas, Brussels sprouts and broccoli. Egg yolks and avocados are sources of low bioavailable lutein and zeaxanthin due to their fat content. Be sure to include some fat in your meal (eg two teaspoons of oil) to optimize carotenoid absorption. Sign up for our weekly Health & Wellness newsletter for the latest news and tips.