Grapefruit benefitS

The grapefruit was bred in the 18th century as a cross between a pomelo and an orange. They were given the name grapefruit because of the way they grew in clusters similar to grapes.

Grapefruits vary in hue from white or yellow to pink and red and can range in taste from very acidic and even bitter to sweet and sugary. Grapefruits are available throughout the year, but the popular Florida and Texas varieties are in season between the months of November and June. Florida is said to be the world's largest grapefruit growing region. Popular varieties of Florida and Texas grapefruit include: Ruby Red, Pink, Flame, Thompson, White Marsh, Star Ruby, Duncan, and Pummelo HB.

Grapefruits are low in calories but are full of nutrients and an excellent source of vitamin A and C. Harvard Medical School states that grapefruit has a glycemic index of 25, suggesting that it does not significantly affect blood sugar and insulin levels. You can find out more about the nutritional breakdown of grapefruits in the Nutritional profile section of this article.

Grapefruits support clear, healthy skin, can help to lower our risk for many diseases and conditions and may even help with weight loss as part of an overall healthy and varied diet.

Possible health benefits of consuming grapefruit

Grapefruits vary in hue from white or yellow to pink and red and can range in taste very acidic and even bitter or sweet and sugary.

Consuming fruits and vegetables of all kinds has long been associated with a reduced risk of many adverse health conditions.

Many studies have suggested that increasing consumption of plant foods like grapefruit decreases the risk of obesity, diabetes, heart disease and overall mortality while promoting a healthy complexion, increased energy, and overall lower weight.

Weight loss

Grapefruit may not be a miracle weight loss food as touted in some previously popular fad diets, but consuming grapefruit as part of a healthy diet may just give you a little boost. The Scripps Clinic 'Grapefruit Diet' study, led by Dr. Ken Fujioka, monitored the weight and metabolic factors of 91 obese men and women for 12 weeks. Each participant was randomly assigned to one of four groups to receive either placebo capsules along with 7 ounces of apple juice, grapefruit capsules with 7 ounces of apple juice, 8 ounces of grapefruit juice with a placebo capsule or half of a fresh grapefruit with a placebo capsule three times a day before each meal.

After 12 weeks, the fresh grapefruit group had lost the most weight at 3.52 lbs, the grapefruit juice group had lost 3.3 lbs, the grapefruit capsule group had lost 2.42 lbs, and the placebo group had lost 0.66 lbs. According to the researchers, there was also a significant reduction in 2-hour post-glucose insulin level in the grapefruit group compared with placebo. Half of a fresh grapefruit eaten before meals was also associated with improved insulin resistance.

 Stroke

According to the American Heart Association, eating higher amounts of a compound found in citrus fruits like oranges and grapefruit may lower ischemic stroke risk for women. Those who ate the highest amounts of citrus had a 19 percent lower risk of ischemic stroke than women who consumed the least.

Blood pressure and heart health

The powerful nutrient combination of fiber, potassium, lycopene, vitamin C and choline in grapefruit all help to maintain a healthy heart.

One  of the study found that a diet supplemented with fresh red grapefruit positively influences blood lipid levels, especially triglycerides. Researchers concluded that the addition of fresh red grapefruit to the diet could be beneficial for people with atherosclerosis wanting to lower their high lipid levels, especially triglycerides.

In one study, those who consumed 4069 mg of potassium per day had a 49% lower risk of death from ischemic heart disease compared with those who consumed less potassium (about 1000 mg per day).

High potassium intakes are also associated with a reduced risk of stroke, protection against loss of muscle mass, preservation of bone mineral density and reduction in the formation of kidney stones.

Increasing potassium intake is also important for lowering blood pressure because of its powerful vasodilation effects.

Digestion and regularity

Grapefruit, because of its water and fiber content, helps to prevent constipation and promote regularity for a healthy digestive tract.

Hydration

As one of the most hydrating fruits in the world made up of 91% water (just below watermelon) and full of important electrolytes, grapefruit is a great snack to have on hand to prevent dehydration.

May be increase your Skin fitness

The antioxidant vitamin C, when eaten in its natural form (in fresh produce as opposed to supplement form) or applied topically, can help to fight skin damage caused by the sun and pollution, reduce wrinkles and improve overall skin texture. Vitamin C plays a vital role in the formation of collagen,  the main support system of skin. Hydration and vitamin A are also crucial for healthy looking skin, both of which grapefruits can provide.

However, it is worth taking note of a study published in June 2015 which suggests that consuming grapefruit juice in large amounts may put us at higher risk of melanoma the deadiest form of skin cancer.

Asthma prevention

The risks for developing  asthma are lower in people who consume a high amount of certain nutrients. One of these nutrients is vitamin C, found in many fruits and vegetables including grapefruit.

Nutritional profile of grapefruit

According to the USDA National Nutrient Database(NND), half of a medium pink grapefruit, (3 ¾ in diameter) contains approximately 52 calories, 0 grams of fat, 0 grams of sodium, 0 grams of cholesterol, 13 grams of carbohydrates (including 8.5 grams of sugar and 2 grams of dietary fiber), and 1 gram of protein. Eating half of a grapefruit per day will meet 64% of your vitamin C needs, 28% of vitamin A, 2% of calcium and 2% of magnesium..

Grapefruits also contain small amounts of vitamin E, thiamin, riboflavin, niacin, folate, pantothenic acid, potassium, phosphorus, manganese, zinc and coper.

Not only are pink grapefruits high in common vitamins and minerals, they also pack a powerful antioxidant punch with lycopene and beta-carotene along with the phytonutrients limonoids and naringenin. Studies have shown that fresh pink or red grapefruit contains higher quantities of bioactive compounds and has significantly higher antioxidant potential than white or yellow grapefruit.

How to incorporate more grapefruit into your diet

Grapefruits should be picked at their peak of ripeness because they do not ripen or improve in quality after being picked, unlike some other fruits. Grapefruits should be stored at room temperature, away from direct sunlight. Choose a grapefruit that is heavy for its size and has a little spring when squeezed.

While it's sometimes hard to find good quality fruits and vegetables in the winter, it is the perfect time to buy citrus. Winter is the peak season for grapefruit, oranges and other citrus fruits.

Quick tips:

§  Keep a bowl on the kitchen table or counter stocked with fresh fruit from the season. Seeing the fruits readily available will likely cause you to choose them as a snack more often than raiding the cupboards for a less healthy snack

Potential health risks of consuming grapefruit

Grapefruit intake should be avoided when taking certain medications, because of enzyme binging ability. This means the medication can pass from your gut to your bloodstream easier and faster than normal. In many cases, these higher levels can be dangerous. Statin drugs, calcium channel blockers and psychiatric drugs are some of the most-common medications that interact with grapefruit.

Also take caution when consuming grapefruit if you have a current kidney condition. Too much potassium can be harmful to those whose kidneys are not fully functional. If your kidneys are unable to remove excess potassium from the blood, it could be fatal.

Those with gastro-esophageal reflux disease (GERD) may experience an increase in symptoms such as heartburn and regurgitation when consuming highly acidic foods such as citrus fruit, however individual reactions vary.

Keep in mind that is the total diet or overall eating pattern that is most important in disease prevention and achieving good health. It is better to eat a diet with a variety than to concentrate on individual foods as the key to good health.

Grapefruits are Rich in the Nutritional Powerhouse Vitamin C

Grapefruit is an excellent source of vitamin C, a vitamin that helps to support the immune system. Vitamin C-rich foods like grapefruit may help reduce cold symptoms or severity of cold symptoms; over 20 scientific studies have suggested that vitamin C is a cold-fighter. Vitamin C also prevents the free radical damage that triggers the inflammatory cascade, and is therefore also associated with reduced severity of inflammatory conditions, such as asthma, osteoarthritis, and rheumatoid arthritis. As free radicals can oxidize cholesterol and lead to plaques that may rupture causing heart attacks or stroke, vitamin C is beneficial to promoting cardiovascular health. Owing to the multitude of vitamin C's health benefits, it is not surprising that research has shown that consumption of vegetables and fruits high in this nutrient is associated with a reduced risk of death from all causes including heart disease, stroke and cancer.

Enjoy Benefits from the Antioxidant Lycopene in Pink and Red Grapefruits

The rich pink and red colors of grapefruit are due to lycopene, a carotenoid phytonutrient. (PLEASE NOTE: Lycopene is only found in pink and red grapefruit. White grapefruit does not provide this carotenoid.) Lycopene appears to have anti-tumor activity. Among the common dietary carotenoids, lycopene has the highest capacity to help fight oxygen free radicals, which are compounds that can damage cells.


Choosing to regularly eat lycopene-rich foods, such as pink grapefruit, and drink green tea may greatly reduce a man's risk of developing prostate cancer, suggests research published the Asia Pacific Journal of Clinical Nutrition(APJCN).


In this case-control study involving 130 prostate cancer patients and 274 hospital controls, men drinking the most green tea were found to have an 86% reduced risk of prostate cancer compared, to those drinking the least.


A similar inverse association was found between the men's consumption of lycopene-rich fruits and vegetables such as tomatoes, apricots, pink grapefruit, watermelon, papaya, and guava. Men who most frequently enjoyed these foods were 82% less likely to have prostate cancer compared to those consuming the least lycopene-rich foods.


Regular consumption of both green tea and foods rich in lycopene resulted in a synergistic protective effect, stronger than the protection afforded by either, the researchers also noted.


Practical Tips: Get in the habit of drinking green tea and eating lycopene-rich foods.

• Take a quart of iced green tea to work and sip throughout the day or take it to the gym to provide prostate protection while replenishing fluids after your workout.
• Pack a ziploc bag of apricots and almonds in your briefcase or gym bag for a handy snack.
• Start your breakfast with a half grapefruit or a glass of grapefruit, apricot, papaya or guava juice.
• Begin lunch or dinner with some spicy tomato juice on the rocks with a twist of lime. Snack on tomato crostini: in the oven, toast whole wheat bread till crusty, then top with tomato sauce, herbs, a little grated cheese, and reheat until the cheese melts.
• Top whole wheat pasta with olive oil, pine nuts, feta cheese and a rich tomato sauce for lunch or dinner.
• For a delicious dessert, drizzle a little honey over a half grapefruit and broil for 2 minutes. Serve topped with a fresh mint leaf.

Grapefruit Juice Ranked among Those Highest in Antioxidant Activity

Not all fruit juices are the same. They differ markedly in the variety of phenolic compounds and antioxidant activity, according to Alan Crozier, Professor of Plant Biochemistry and Human Nutrition, who, with colleagues at the University of Glasgow, evaluated 13 commercially available popular juices.


Concord grapes came out on top with the highest and broadest range of polyphenols and the highest overall antioxidant capacity. (The main components in purple grape juice were flavan-3-ols, anthocyanins, and hydroxycinnamates, together accounting for 93% of the total phenolic content.)


Other top scorers were cloudy apple juice, cranberry juice and grapefruit juice.
Results for the red grape juice were said to be equal to those for a Beaujolais red wine. Interestingly, however, white grape juice, mainly containing hydroxycinnamates, had the lowest total phenolic content.


The products analyzed were: Spray Classic Cranberry; Welch's Purple Grape; Tesco Pure Pressed Red Grape; Pomegreat Pomegranate; Tesco Pure Apple (clear); Copella Apple (cloudy); Tesco Pure Grapefruit; Tesco Value Pure Orange (concentrate); Tropicana Pure Premium Smooth Orange (squeezed); Tropicana Pure Premium Tropical Fruit; Tesco Pure Pressed White Grape; Tesco Pure Pineapple; Del Monte Premium Tomato.


Dr. Crozier's findings come shortly after those of the Kame project, which indicated that long-term fruit juice consumption can provide protection against Alzheimer's disease (Dai et al., Am J Med), and suggest that, since each fruit juice contains its own array of protective phenols, drinking a variety may offer the best protection. Practical Tip: "The message is to mix these juices during the week. That way you will get all the compounds with anti-oxidant activity. If you drink only one juice you risk missing out on the compounds in the others," explained Crozier.

Limonoids in Grapefruit Promote Optimal Health

Phytonutrients in grapefruit called limonoids inhibit tumor formation by promoting the formation of glutathione-S-transferase, a detoxifying enzyme. This enzyme sparks a reaction in the liver that helps to make toxic compounds more water soluble for excretion from the body. Pulp of citrus fruits like grapefruit contain glucarates, compounds that may help prevent breast cancer.


In animal studies and laboratory tests with human cells, limonoids have been shown to help fight cancers of the mouth, skin, lung, breast, stomach and colon. Now, scientists from the US Agricultural Research Service (ARS) have shown that our bodies can readily absorb and utilize a very long-acting limonoid called limonin that is present is citrus fruits in about the same amount as vitamin C.


In citrus fruits, limonin is present in the form of limonin glucoside, in which limonin is attached to a sugar (glucose) molecule. Our bodies easily digest this compound, cleaving off the sugar and releasing limonin.


In the ARS study, 16 volunteers were given a dose of limonin glucoside in amounts ranging from those that would be found in from 1 to 7 glasses of orange juice. Blood tests showed that limonin was present in the plasma of all except one of the subjects, with concentrations highest within 6 hours after consumption. Traces of limonin were still present in 5 of the volunteers 24 hours after consumption!


Limonin's bioavailability and persistence may help explain why citrus limonoids are potent anti-carcinogens that may prevent cancerous cells from proliferating. Other natural anti-carcinogens are available for much less time; for example, the phenols in green tea and chocolate remain active in the body for just 4 to 6 hours.


The ARS team is now investigating the potential cholesterol-lowering effects of limonin. Lab tests indicate that human liver cells produce less apo B when exposed to limonin. Apo B is a structural protein that is part of the LDL cholesterol molecule and is needed for LDL production, transport and binding, so higher levels of apo B translate to higher levels of LDL cholesterol.

Grapefruit Lowers Cholesterol

Grapefruit contains pectin, a form of soluble fiber that has been shown in animal studies to slow down the progression of atherosclerosis. In one study, animals fed a high-cholesterol diet plus grapefruit pectin had 24% narrowing of their arteries, while animals fed the high-cholesterol diet without grapefruit pectin had 45% narrowing.


Both blond and red grapefruit can reduce blood levels of LDL ("bad") cholesterol, and red grapefruit lowers triglycerides as well, shows a study published in the Journal of Agricultural and Food Chemistry.


Israeli researchers from the Hebrew University in Jerusalem first tested the antioxidant potential of blond and red grapefruits and then their cholesterol-lowering potential in humans. The test tube research showed that red grapefruit contains more bioactive compounds and total polyphenols than blond, but both grapefruits are comparable in their content of fiber, phenolic and ascorbic acids, and the flavonoid, naringinen, although red grapefruit contains slightly more flavonoids and anthocyanins.


In this recent study, participants added either red grapefruit, blond grapefruit or no grapefruit to their daily diet. The results indicated that both types of grapefruit appeared to lower LDL cholesterol in just 30 days: total cholesterol by 15.5% in those eating red grapefruit and 7.6% in those eating blond grapefruit; LDL cholesterol by 20.3% and 10.7% respectively; and triglycerides by 17.2% and 5.6% respectively. No changes were seen in the control group (those that didn't eat any grapefruit).


Both red and blond grapefruits both positively influenced cholesterol levels, but red grapefruit was more than twice as effective, especially in lowering triglycerides. In addition, both grapefruits significantly improved blood levels of protective antioxidants. Red grapefruit's better performance may be due to an as yet unknown antioxidant compound or the synergistic effects of its phytonutrients, including lycopene.
In response to this rapid and very positive outcome, the researchers concluded that adding fresh red grapefruit to the diet could be beneficial for persons with high cholesterol, especially those who also have high triglycerides.


One caveat, however: Compounds in grapefruit are known to increase circulating levels of several prescription drugs including statins. For this reason, the risk of muscle toxicity associated with statins may increase when grapefruit is consumed. (See our Individual Concerns section for more information.)

Grapefruit Juice May Prevent Kidney Stones

Want to reduce your risk of calcium oxalate kidney stones? Drink grapefruit juice. A study published in the British Journal of Nutrition found that when women drank 1/2 to 1 liter of grapefruit, apple or orange juice daily, their urinary pH value and citric acid excretion increased, significantly dropping their risk of forming calcium oxalate stones.

Grapefruit's Potential Protection against Colon Cancer

Not only are grapefruit rich in vitamin C, but new research presented at the 228th National Meeting of the American Chemical Society provides two more reasons to drink grapefruit juice: protection against lung and colon cancer.


In humans, drinking three 6-ounce glasses of grapefruit juice a day was shown to reduce the activity of an enzyme that activates cancer-causing chemicals found in tobacco smoke. In rats whose colons were injected with carcinogens, grapefruit and its isolated active compounds (apigenin, hesperidin, limonin, naringin, naringenin, nobiletin) not only increased the suicide (apoptosis) of cancer cells, but also the production of normal colon cells.


Researchers also confirmed that grapefruit may help prevent weight gain by lowering insulin levels.

Grapefruit's Naringenin Repairs DNA

Naringenin, a flavonoid concentrated in grapefruit, helps repair damaged DNA in human prostate cancer cells (cell line LNCaP), reports a lab study published in the Journal of Nutritional Biochemistry.


The risk of prostate cancer, the most commonly diagnosed cancer in men in the U.S, increases with age since the older we become, the more times our cells have divided and the greater the chance for DNA mutations to occur. DNA repair is one of the body's primary defense mechanisms against the development of cancer since it removes potentially cancer-causing mutations in cells.


Naringenin helps restore health to damaged DNA by inducing two enzymes that repair DNA during the replication stage. These enzymes, 8-oxoguanine-DNA glycosylase 1 (hOGG1), and DNA polymerase beta (DNA poly beta), are both involved in the DNA base excision repair (BER) pathway.


The scientists in this study exposed cell cultures to 80 micromoles per liter, an amount we cannot achieve by consuming grapefruit since research indicates that only between 2 and 15% flavonoids in the food we consume are absorbed in the GI tract, and plasma concentrations after eating flavonoid-rich foods range from 0.5 to 1 micromole per liter.
Fortunately, however, the researchers also demonstrated that the concentration of naringenin inside the cells that was needed for its beneficial effects was only 5% of the amount in the medium, and this amount is physiologically achievable in our tissues.
Unlike many other cancers, prostate cancer is slow growing initially and often remains undetectable for a long time. Enjoying grapefruit regularly may be one way to prevent its progression by promoting the repair of damaged DNA in prostate cells, thus preventing them from becoming cancerous.

Description

The grapefruit is a large citrus fruit related to the orange, lemon and pomelo. Grapefruits are categorized as white (blond), pink or ruby. However, this terminology doesn't reflect their skin color, which is either yellow or pinkish-yellow, but rather describes the color of their flesh.


Grapefruits usually range in diameter from four to six inches, with some varieties featuring seeds while others are seedless. The wonderful flavor of a grapefruit is like paradise, just as its Latin name Citrus paradisi connotes. It is juicy, tart and tangy with an underlying sweetness that weaves throughout.

About

Grapefruits have a rather recent history, having been discovered in Barbados in the 18th century. Many botanists think the grapefruit was actually the result of a natural cross breeding which occurred between the orange and the pomelo, a citrus fruit that was brought from Indonesia to Barbados in the 17th century.
The resulting fruit was given the name "grapefruit" in 1814 in Jamaica, a name which reflects the way it's arranged when it grows—hanging in clusters just like grapes.
Grapefruit trees were planted in Florida in the early 19th century, although they did not become a viable commercial crop until later that century. Florida is still a major producer of grapefruits, as is California, Arizona and Texas. Other countries that produce grapefruits commercially include Israel, South Africa and Brazil.

How to chose and Store

A good grapefruit doesn't have to be perfect in color. Skin discoloration, scratches or scales may affect the appearance of a grapefruit, but they do not impact the taste or texture quality.


Signs of decay include an overly soft spot at the stem end of the fruit and areas that appear watersoaked. These forms of decay usually translate into poor taste—a flavor that is less vibrant and more bitter than a good quality grapefruit.


The fruits should be heavy for their size as this usually indicates that they feature thin skins and therefore a higher concentration of juicier flesh. Those that have overly rough or wrinkled skin usually tend to be thick skinned and should be avoided.


Grapefruits should be firm, yet slightly springy when gentle pressure is applied. While chilled grapefruits do not have an apparent fragrance, those kept at room temperature should have a subtly sweet aroma. Grapefruits can be purchased throughout the year although the height of the season ranges from winter through early spring. For the most antioxidants, choose fully ripened grapefruit.


We encourage the purchase of certified organically grown foods, and grapefruit is no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including grapefruit. If you are shopping in a large supermarket, your most reliable source of organically grown grapefruit is very likely to be grapefruit that displays the USDA organic logo.
Since grapefruits are juicier when they're slightly warm rather than cool, store them at room temperature if you are planning on consuming them within a week of purchase. If you will not be using them within this time period, store them in the refrigerator crisper where they will keep fresh for two to three weeks.

Individual Concerns

Grapefruit and Drug Interactions

Check with your healthcare practitioner about consuming grapefruit juice if you're taking pharmaceutical drugs. Certain pharmaceutical drugs combined with grapefruit juice become more potent. Compounds in grapefruit juice, including naringenin, slow the normal detoxification and metabolism processes in the intestines and liver, which hinders the body's ability to breakdown and eliminate these drugs.



These interactive drugs include the immunosuppressent cyclosporine and calcium channel blocker drugs, such as felodipine, nifedipine and verapamil. Other drugs whose bioavailability is enhanced by grapefruit juice are the antihistamine terfenadine, the hormone estradiol and the antiviral agent saquinavir.



Research also indicates that individuals taking statin drugs should avoid grapefruit. Grapefruit increases the amount of statin drug that reaches the general circulation in two ways. First, grapefruit contains a compound called naringenin, which inactivates an enzyme (cytochrome P450 3A4) in the small intestine that metabolizes statin drugs. Secondly, grapefruit also inhibits P-glycoprotein, a carrier molecule produced in the intestinal wall that would normally transport the statin drug back to the gut. The end result of these two mechanisms is that much more of the statin drug enters the systemic circulation than would normally be the case, leading to a build up in statin levels that can be quite dangerous, and may trigger a rare but serious statin-associated disease called rhabdomyolysis. Rhaddomyolysis affects muscle tissue, usually causing temporary paralysis or weakness, unless the muscle is severely injured.