Watermelons contain an ingredient called citrulline that can trigger production of a compound that helps relax the body's blood vessels, similar to what happens when a man takes Viagra, said scientists in Texas, one of the nation's top producers of the seedless variety.
Found in the flesh and rind of watermelons, citrulline reacts with the body's enzymes when consumed in large quantities and is changed into arginine, an amino acid that benefits the heart and the circulatory and immune systems.
"Arginine boosts nitric oxide, which relaxes blood vessels, the same basic effect that Viagra has, to treat erectile dysfunction and maybe even prevent it," said Bhimu Patil, a researcher and director of Texas A&M's Fruit and Vegetable Improvement Center. "Watermelon may not be as organ-specific as Viagra, but it's a great way to relax blood vessels without any drug side effects."
Viagra, also known as sildenafil, is manufactured by Pfizer Inc.
Todd Wehner, who studies watermelon breeding at North Carolina State University, said anyone taking Viagra shouldn't expect the same result from watermelon.
"It sounds like it would be an effect that would be interesting but not a substitute for any medical treatment,"
The nitric oxide can also help with angina, high blood pressure and other cardiovascular problems, according to the study, which was paid for by the U.S. Department of Agriculture.
More citrulline -- about 60 percent -- is found in watermelon rind than in the flesh, Patil said, but that can vary. But scientists may be able to find ways to boost the concentrations in the flesh, he said.
Citrulline is found in all colors of watermelon and is highest in the yellow-fleshed types, said Penelope Perkins-Veazie, a USDA researcher in Lane, Oklahoma.
She said Patil's research is valid, but with a caveat: One would need to eat about six cups of watermelon to get enough citrulline to boost the body's arginine level.
"The problem you have when you eat a lot of watermelon is you tend to run to the bathroom more," Perkins-Veazie said.
Watermelon is a diuretic and was a homeopathic treatment for kidney patients before dialysis became widespread.
Another issue is the amount of sugar that much watermelon would spill into the bloodstream -- a jolt that could cause cramping, Perkins-Veazie said.
Patil said he would like to do future studies on how to reduce the sugar content in watermelon.
The relationship between citrulline and arginine might also prove helpful to those who are obese or suffer from type-2 diabetes. The beneficial effects -- among them the ability to relax blood vessels, much like Viagra does -- are beginning to be revealed in research.
Citrulline is present in other curcubits, like cucumbers and cantaloupe, at very low levels, and in the milk protein casein. The highest concentrations of citrulline are found in walnut seedlings, Perkins-Veazie said.
"But they're bitter and most people don't want to eat them," she said.
A good sex life doesn’t just happen – it requires a little help, which means a balanced and nutrients diet combined with regular moderate exercise and a positive attitude. These are all key elements in helping to keep your sex drive high and your reproductive system in good working order. It cannot be ignored that there are certain nutrients which have the power to regulate the levels of sex hormones in your body, and some can even help to protect your reproductive system from the potentially damaging effects of infection or disease.
* A lack of zinc can cause infertility and impotence, and while moderate amounts of alcohol can help people to feel relaxed.
* Caffeine in coffee, tea and cola drinks can reduce libido.
* Being either overweight or underweight (Click here to check your target weight) can reduce the libido and impair fertility. A certain level of body fat is necessary ovulation and menstruation, and when fat drops below a certain critical point, ovulation and menstruation both cease. At the other extreme, obesity can impair ovulation in women.
* A negative attitude to your weight or body shape can dent your confidence in sex and relationships.
There are certain foods that are not only delicious but also contain the necessary nutrients to maintain your reproductive health and your libido. These will contribute to your healthy sexuality by maintaining your system in good condition, helping you to regulate your hormonal cycles and boosting your fertility. Besides, the fast pace of modern life leads to stress, tiredness and sometimes a lack of sexual energy. Foods indicated below can help to combat this.
Vitamin A :
Maintains the health of the epithelial tissues which line all the external and internal surfaces of the body, including the linings of the vagina and the uterus in women. Liver, egg, yolk, cheese, butter and carrots are good sources.
Vitamin B :
Deficiencies of both vitamin B2 and folic acid have been linked with infertility, and women planning a pregnancy should ensure that they eat plenty of foods rich in folic acid well before conception. Watercress is a particularly good source of folic acid. Lean meat, chicken, fish, wheatgerm, brewer’s yeast, beans and pulses, peanuts and bananas provide B6. These foods are all rich in folic acid. Dark green leafy vegetables such as spinach and cabbage, liver, oranges, avocado, beetroot and broccoli are all rich in folic acid.
Vitamin C :
ncreasing vitamin C intake may be helpful in boosting fertility, particularly for men; tests have shown that taking 500-1000 milligrams a day can increase the number and quality of sperm produced and reduce abnormalities. This vitamin may also help to prevent the condition known as ‘agglutination', in which the sperm becomes stuck together and are unable to reach the egg. All fruit and vegetables – particularly kiwi fruit, peppers, blackcurrants, strawberries and citrus fruits – contain abundant quantities of vitamin C.
Vitamin E :
A powerful antioxidant, vitamin E helps to protect the ova from damage. Sunflower, safflower oils and some vegetable oils, nuts and seeds, margarine, wheatgerm and avocados contain high levels.
There is probably more than a grain of truth in the theory that oysters are good for your sex life, as they are the richest food source of zinc, and zinc is known to be one of the key nutrients involved in enhancing libido & the production of sperm. Low levels of zinc have been linked both with poor libido in women and with a low sperm count in men. You can obtain zinc from shellfish (particularly oysters), wholemeal bread, brown rice, dark green leafy Vegetables, lean red meat and turkey.
This mineral is vital to ensure the production of healthy ova & sperms. Learn meat, offal, brown rice and porridge oats are good sources.
The metabolism of the female hormone oestrogen depends on manganese. It follows that a deficiency of manganese will significantly reduce fertility in women. Spinach, chestnuts, tea, oats, wholegrain cereals, wheatgerm, raisins, pineapple, beans, peas and nuts are all good sources of manganese.
Essential fatty acids :
Linoleic acid is important for sperm production. Sunflower and vegetables oils and nuts contain plentiful amounts.
Chemical of plant origin that resemble the female hormone oestrogen are abundant in Soya bean and Soya products such as Soya drinks and tofu. They may also help protect against prostate and other cancers by preventing the growth of tumors.
Fruits and vegetables are high in antioxidants which may lower the risk of cervical cancer. They neutralize the harmful substances produced by the body.
Food and sexual prowess has been linked throughout history. Prunes, ginseng, aniseed, onion and garlic, carrots, ginger, artichokes, Aubergine
are some of the foods that have been claimed to enhance sexual pleasure.