Can Colorful Foods Help Reproductive Health for Women and Men?
You have heard time and time again that consuming copious amounts of colorful fruits and vegetables is beneficial to your health, thanks to the many phytonutrients such as carotenoids. But did you ever think this could also impact your ability to get pregnant?
Infertility is a common problem, with about 12 percent of American women experiencing difficulty getting pregnant. There are many reasons couples may find it hard to conceive. In couples experiencing infertility, it is due to the female about a third of the time, the male about a third of the time, and both or unknown factors the other third.
Many nutrients can impact a couple’s ability to get pregnant, including carotenoids. These important antioxidants provide many benefits to both male and female reproductive health.
Carotenoids are a family of plant pigments that provide important health benefits. Several carotenoids are pro-vitamin A, which means they can be converted into vitamin A in the body. Vitamin A plays a key role in eye health, the genesis of organs, immune health, and differentiation of tissue. All of the carotenoids, as well as vitamin A, also perform important activities as antioxidants. Consumption of carotenoids has been linked to a reduction of several chronic illnesses, including cancer and cardiovascular disease, as well as benefits to reproductive health.
The Positive Impact on Male Fertility…
Oxidative stress has the potential to significantly affect male fertility, mainly due to the negative impact of reactive oxygen species on sperm quality and function. Therefore, it is important for men to consume sufficient antioxidants, such as carotenoids, to counter any excess oxidative stress and remain fertile.
In one study on sticklebacks, males that consumed higher levels of carotenoids were more successful in mating, regardless of the level in females. This effect was most likely due to the protective antioxidant effects on the sperm. This study might have looked at birds, but there is some relevance to humans as well.
In a study on humans, the blood and semen samples of infertile men had a much lower antioxidant capacity, including reduced levels of carotenoids and other antioxidants such as vitamin E, compared to fertile men. There was also a positive correlation between the concentrations of carotenoids and the total antioxidant capacity with the concentration, morphology, and motility of the sperm. Based on this evidence, it would appear that consuming foods rich in carotenoids benefit male fertility.
And Female Fertility
There is also a link between carotenoids and female fertility. One study reviewed the effect of several different antioxidants on the menstrual cycle of healthy, premenopausal women with regular cycles. Interestingly, they found that there was a significant variation in the level of antioxidants in the different phases of the cycle. During menses, antioxidant levels were lower, including those of beta-carotene, lycopene, and lutein. Additionally, there was a positive association between the level of antioxidants and testosterone and steroidal levels. The researchers stipulated that antioxidants play a role in steroidogenesis, which is the production of the sex hormones, including estrogen and testosterone. This relationship remained true even after adjusting for any potential oxidative stress.
Another area where beta-carotene might help with female fertility is through enhancing ovarian function and the synthesis of progesterone. In a study on goats, those supplemented with beta-carotene had more progesterone synthesis. This is an important component of fertility, as progesterone is essential for ovulation, healthy oocytes, maintaining the uterine, and creating a nourishing and healthy environment for the embryo. The researchers suggested that the benefits provided by beta-carotene might be due to two main factors. First, its antioxidant capacity might enhance the progesterone synthesis in the luteal cells, since steroidogenesis results in increased oxygen radicals requiring mitigation. Beta-carotene might also activate the protein kinase A second messenger system to stimulate LH (luteinizing hormone), which plays a key role in stimulating the synthesis of progesterone.
The Role in Fertilization
Carotenoids also play a role in successful fertilization. There needs to be the perfect balance between ROS (reactive oxygen species) and antioxidants in both eggs and sperm for fertilization to occur. In one study, consuming antioxidants led to a shorter time to pregnancy in couples who were undergoing treatment for unexplained fertility. Supplementation of beta-carotene positively affected those with a BMI above 25, something that makes it harder to conceive. However, it did lead to a longer time to pregnancy in women over the age of 35, which might be due to an alteration in progesterone secretion.
The Relationship with Estrogen
Studies have found a potential inverse association between carotenoids and estrogen, which might be beneficial in preventing estrogen-dependent cancers. A study on post-menopausal women found that alpha and beta-carotene had significant inverse associations with the level of estradiol (E2), even after adjusting for confounding elements. Based on the studies, it appears likely that beta-carotene has a larger role in mitigating estrogen through modulating the activity of E2.
Another study found that carotenoids had the capacity to inhibit E2 signaling, as well as E2 and genistein-induced cell proliferation. This effect could be the reason they reduce estrogen-induced cancers in both premenopausal women and postmenopausal women with estrogen-receptor positive cancers.
A Note on Obesity and Carotenoid Status
An important thing to note is that obesity might affect levels of carotenoids, and this is not due to differences in dietary intake. In one study, researchers found that the levels of carotenoids in obese women (based on BMI) were significantly lower than that of normal-weight women. This reduction was three times greater for the pro-vitamin A carotenoids, which includes alpha and beta-carotene and cryptoxanthin compared with the carotenoids that do not convert to vitamin A (lycopene, alpha cryptoxanthin, anhydrolutein, and lutein/zeaxanthin). It is unknown as to why this lowering occurs but could be due to a higher metabolism to vitamin A to help with immune function and the requirement of carotenoids for antioxidant activity, since obesity is related to higher levels of oxidative stress.
Obesity is associated with both male and female fertility, and the connection between fertility and carotenoids might be an element of the complex relationship between obesity and fertility. It might be reasonably inferred, based on this information, that those who are overweight or obese might wish to take extra precautions to ensure sufficient consumption of carotenoids, especially when trying to become pregnant.
The Effects on Menopause
The end of a woman’s fertility marks menopause. It occurs once the ovarian reserve is exhausted, although certain factors, like a poor diet, can lead to an early loss of this reserve. One study found that there was a positive correlation between beta-cryptoxanthin, a carotenoid, and the age in which women entered natural menopause, even after adjusting for covariants such as obesity, smoking, and diet. The researchers concluded that consuming a diet high in fruit, especially one that contains at least 400 mcg of beta-cryptoxanthin per day, could delay the natural deterioration of the ovaries that come with age by 1.3 years. This is pretty easy to do, as long as you consume the right beta-cryptoxanthin-rich foods. For example, one cup of cubed butternut squash has 6,388 mcg, 1 cup of papaya contains 854 mcg, 1 cup of tangerines contains 794 mcg, and 1 cup of raw orange juice contains 405 mcg of beta-cryptoxanthin. Peppers, peaches, and persimmons are also rich in this carotenoid.
Menopause comes with a number of physiological changes in women, and it is associated with an increase in oxidative stress and a reduction in antioxidant capacity during menopause. Women might want to consume extra antioxidants to blunt this effect. In a study on menopause-induced rats, researchers treated rats with vitamin A and found that after 30 days, the rats experienced improved antioxidant capacity. Therefore, getting high-carotenoid foods in the diet might help to mitigate some of the effects of menopause, especially those related to oxidative stress.
Carotenoids might also help prevent osteoporosis in postmenopausal women. A study on postmenopausal Japanese women also found an inverse relationship between high levels of carotenoids, specifically beta-carotene and beta-cryptoxanthin, and a change in bone mineral density. It is common for the blood levels of carotenoids to decrease in postmenopausal women, but consuming a diet high in fruits and vegetables leads to a higher level of carotenoids. Therefore, women will want to consume plenty of carotenoid-rich food before, during, and after menopause to enhance their reproductive health.
In summary, eating carotenoid-rich foods has the ability to increase fertility, reduce oxidative stress, relieve some of the effects of menopause, and lower the risk of certain cancers. With so many different health benefits relating to the sex hormones, especially for women, you want to be sure you have plenty of them in your diet.
So what can you do to improve your carotenoids level? Consume lots of fruits and vegetables, especially those rich in carotenoids, such as green leafy vegetables, carrots, apricots, pumpkin, sweet potato, and tomatoes. If you are looking for the best source of bioavailable carotenoids, turn to delicious papaya. A study found that it had three times higher bioavailable beta-carotene than carrots and tomatoes, as well as higher quantities of bioavailable beta-cryptoxanthin and lycopene.