Grapefruit: Health Benefits, Facts, Research

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 vitamins 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.

This MNT Knowledge Center feature is written by our registered dietitian and nutritionist, Megan Ware, and forms part of a collection of articles about the health benefits of popular foods.

At the end of this article you will see links to recent research about grapefruit published by MNT. It is important to note that although we discuss the possible health benefits of grapefruit, grapefruit intake should be avoided when taking certain medications. Please read the health risks section on the second page of this article for more information on this.

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.

1) 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.

2) 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.⁵

3) 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 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).³

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.³

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

4) Cancer

As an excellent source of the strong antioxidant vitamin C as well as other antioxidants, grapefruit can help combat the formation of free radicals known to cause cancer. Lycopene intake has been linked with a decreased risk of prostate cancer prevention in several studies and foods high in vitamin C and beta-carotene have been shown to lower the risk of esophageal cancer in particular.

5) Digestion and regularity

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

6) 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.

7) Skin

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 deadliest form of skin cancer.

8) 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.

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On the next page we look at the nutritional breakdown of grapefruit, ways in which to incorporate more grapefruit into your diet and the possible health risks associated with consuming grapefruit, including grapefruit's interference with certain medications.

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