Fruits make you indomitable, literally. Several studies show that eating five helpings — five cupfuls — of raw fruit prevent cancers, heart disease, diabetes and osteoporosis.
In citrus fruits such as oranges, mandarin and lemons, the health benefits lie in of the presence of pectin, a natural compound that helps prevent prostate and other cancers, reports a study in the Journal of Agriculture and Food Chemistry.
The study was done by Dr Bhimu Patil, director of Texas A&M University's Vegetable and Fruit Improvement Centre, and colleagues. During a one-day stop in New Delhi, Patil spoke about his groundbreaking work that proved pectin worked against cancer cells and held promise as a dietary preventative for disease.
"Pectin is a complex carbohydrate found in many plants, but is most abundant in citrus fruits. It has already been shown to reduce cholesterol and blood sugar. While our study focused mainly on prostate cancer, pectin may show similar benefits in inhibiting other types of cancer," Patil told Hindustan Times.
Another study done by Patil's team shows that orange and grapefruit juice given regularly prevented osteoporosis, a debilitating disease that causes bones to become brittle with age and break. The study was published in Nutrition, which ran the research as its lead article.
Few people are aware about the health benefits of fruits on bone health. "One of the reasons for reduced bone density is the increase in cell-damaging oxidants produced by the body's metabolic process. Our studies showed that both grapefruit and orange juice increased antioxidants in the rats' systems, which protects the bone cells from damage," he explains.
Earlier studies have shown that pectin can also help reduce levels of artery-blocking "bad" cholesterol (low density lipoprotein or LDL) in the blood and maintain blood sugar at a healthy concentration.
"Citrus fruit are a vast reservoir of anti-carcinogens and a storehouse of health-promoting nutrients," says Patil, who received his undergraduate degree at the University of Agricultural Sciences in Bangalore before moving to the US.
If locally grown, a whole fruit packs in a lot more nutritional punch than its juice. The fibre in a whole fruit also fills people up, so they tend to eat less. "Fruits need to be stored at temperatures below 15 degrees centigrade — nine degrees in the case of citrus — to ensure they retain their nutritional value. Up to 60 per cent vitamin C is lost within two months of the fruit being plucked, which is the time it takes for artificially-ripened fruit to reach the market in many parts of the world," says Patil.
If you are not sure about how fresh the produce is, it may be a good idea to opt for juices for the nutritional value and get the fibre from other sources, recommends Patil.
The nutritional components of many packaged juices are preserved because the fruit is freshly picked and juiced. PepsiCo, the makers of Tropicana, say some, like mandarins and oranges, are squeezed with the skin to maximise nutritional content. "Independent studies that compared commercially squeezed juice with domestic squeezed juice found the levels of beneficial phytochemical and flavonoid to be higher in commercially squeezed juice," says Yashna Harjani, nutrition specialist, Asia PepsiCo.
But don't go for citrus alone. "In general, people should eat different coloured fruit to get all of the beneficial compounds. And make sure you eat them fresh," says Patil.