Leslie Beck, a Toronto-based private practice nutritionist, is the director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD
Healthy eating recommendations 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 requirements 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 needs increase to protect against osteoporosis.
According to researchers at the University of Georgia, there’s another dietary component women should be proactive 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
Although women tend to live longer than men, 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, states that women account for 70 percent of all dementia cases, most notably Alzheimer’s dementia and age-related macular degeneration.
Causes 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: emphasis on lutein
In the new review, researchers argue that higher rates of neurodegenerative diseases among women may be reduced by a diet high 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 (eg carrots, sweet potatoes, mango, spinach), lutein and zeaxanthin (eg spinach, kale, chard), lycopene (eg tomato sauce, tomato juice, watermelon) and beta-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 detail vision. Here, they protect eye tissues from light-induced free radical production. 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, the elderly, and adults with cognitive impairments show 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. However, data from observational studies suggest 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 are particularly protective.
Interestingly, the latest research shows that women need more carotenoids than men to protect themselves from disease. One reason has to do with how they are stored in the body.
Carotenoids, which are fat-soluble, are stored in adipose tissue. Women have more body fat on average than men. Research shows that despite similar intake and blood levels of lutein and zeaxanthin, women have higher levels of them in their fat tissue than men.
These stores are useful during pregnancy and breastfeeding. But, according to the researchers, this also means that less lutein and zeaxanthin is available to the eyes and brain, putting women at greater risk of degenerative problems later.
They concluded that “given the high likelihood of help and the low likelihood of harm, targeting women’s lutein and zeaxanthin intake is a wise strategy.”
What are the best food sources of lutein?
Excellent sources of lutein and zeaxanthin are cooked leafy greens, including spinach (15 mg per half cup), kale (12.5 mg), Swiss chard (9.5 mg), dandelion leaves (9 mg), dandelion leaves ( 5 mg) and mustard leaf (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, green peas, Brussels sprouts and broccoli. Egg yolks and avocados are low-available sources of lutein and zeaxanthin, thanks to their fat content.
Be sure to include some fat in your meal (eg two teaspoons of butter) to optimize carotenoid absorption.
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