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In a nutshell

In a nutshell
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First Published: Thu, May 22 2008. 11 09 PM IST
Updated: Thu, May 22 2008. 11 09 PM IST
Ongoing studies at the University of California, Los Angeles (UCLA) hope to prove that a daily ration of snack pistachios can keep you trim. Earlier studies have already shown that pistachios are heart-friendly and have cholesterol-lowering properties. Another recent study in the British Journal of Nutrition, endorsing the findings of a 2003 study in the International Journal of Obesity, shows that a serving of almonds daily, apart from lowering cholesterol, can also significantly contribute to weight management.
So, what happened to old theories about nuts being fattening?
Health benefits
Nut used to be considered fattening because of their high calorie count. But, now that nutrition science has started sifting the difference between good fats and bad fats, nuts are back in favour.
Heart-friendly: David Heber—director of the UCLA Center for Human Nutrition, and well-known author and obesity treatment and prevention expert—says nuts are loaded with monounsaturated fats and polyunsaturated fats, basically the good fats, which are heart-friendly. In addition, he says nuts—especially pistachios—are full of phytosterols (plant sterols that are believed to lower the absorption of cholesterol from other foods).
Studies from Spain on people with moderately high blood cholesterol levels have shown that a walnut-added diet (10 walnuts/day) significantly helps dilate or widen the blood vessels. According to the Harvard Institute of Public Health, the omega-3 fatty acids in walnuts also help prevent erratic heart rhythms and blood clots.
Daily supplement: Nuts are an amazing source of protein and dietary fibre and full of disease-fighting vitamins and minerals such as vitamin E (antioxidant properties), folic acid, niacin, magnesium, vitamin B6, zinc, copper, thiamin and potassium.
Cancer preventive: Nuts are loaded with polyphenols (antioxidants that are found in red wine, green tea and olives) that help prevent cancer. It has been suggested that the presence of selenium in nuts (the highest amount is found in Brazil nut) also helps prevent prostate cancers.
Diabetes control: The high dietary fibre found in nuts helps control sugar. A number of trials on diabetic subjects have shown that intake of nuts improves, rather than impairs, lipid profile in the blood.
Weight management: According to the recent study in the British Journal of Nutrition, the high fibre content in almonds appears to block some of the fat they contain. Nuts such as pistachios and groundnuts are also relatively “slow” snacks—shelling them extends the time taken to eat them, thereby regulating portions. Also, a small amount of nuts can induce satiety.
Is there a king among nuts?
This is the grey zone, really— we are told that tree nuts are better than ground nuts (which are incidentally from the legume family and hence not true nuts), and it is also argued that pistachios, almonds and walnuts are better than cashews.
Dr Heber sticks his neck out and says that the pistachio is undoubtedly the king of nuts. In support of his theory, the author of the highly successful book What Colour is Your Diet? points out that pistachios are the only nuts with colour—the slight tinge of green, he says, indicates the presence of lutein, an antioxidant needed to maintain eye health, and which prevent age-related macular degeneration.
The presence of a purplish hue in pistachios indicates anthocyanin, an antioxidant found in cranberry. Dr Heber says consumption of pistachios slows ageing.
It has anti-inflammatory properties, prevents heart disease and keeps the brain active—and, with one of the lowest quantities of saturated fat and calorie content among nuts, it is great for weight management. Those promoting almonds claim that amongst the tree nuts, almonds are the highest in key nutrients such as protein, calcium, dietary fibre and vitamin E, and the lowest in saturated fat. Similarly, walnut, groundnut, hazelnut and macadamia nut people have their own claims.
Given that each nut has its own benefits (for instance, cashews are richest in magnesium, while Brazil nuts have the highest phosphorous content), it’s best to follow the common sense approach.
Nutritionists advise that just as you would consume a variety of vegetables, it is best to have a mixed platter of nuts to get the whole range of benefits.
How much, and in what form?
Nuts probably earned their bad reputation because of excesses —people tend to eat too many at one go, have them fried in oil, and smothered with salt and spices. Doctors say that anything in excess of 20 nuts at a time can cause problems from indigestion to excess weight gain. So, just have a handful a day.
Children under 3 should not be given whole nuts as there is danger of choking—also, with nut allergy becoming increasingly common, it’s best to avoid them unless it’s established that no allergy exists (see box).
Nuts are pretty versatile and are healthy consumed plain, as topping on salads, sprinkled over your morning cereal, as dry roasted snacks or, if you have a sweet tooth, coated with honey or jaggery.
According to Dr Heber, nuts are best after you exercise. Marketers today are also pitching roasted and salted nuts against chips as a “super snack food”. Karen Lapsley, director of scientific affairs, Almond Board of California, says there is no nutrient loss if you dry roast nuts; these can effectively replace less nutritious food as a healthy teatime snack.
Avoid frying in oil, warn nutritionists, as high temperatures destroy most of the vitamin E, B and essential fatty acids in nuts.
Nuts have to be stored in cool and dry conditions as they are prone to contamination by moulds. Aflatoxin contamination is a big issue, so make sure you buy reputed brands. According to Ravinder Mehta, business head (dry fruits and nuts), Reliance Retail, roasted and salted pistachios and cashew nuts have a long shelf life (more than a year at least) while almonds, because of their high oil content, tend to go rancid faster. Dr Lapsley disagrees, however, maintaining that almonds can stay for at least two years if they are stored away from high temperature or high humidity areas.
An almond myth
Soaking almonds overnight and peeling the skin off is believed to help in faster digestion and absorption.The fact is, almond skin also contributes to the fibre content, and contains antioxidants as well. Dr Lapsley says that soaking almonds is good, as long as you drink up the water in which it is soaked.
Nut allergies: emerging reality
Doctors in Delhi report that food allergies are on the rise. Changing lifestyles are the cause, and according to Mukesh Giridhar, consultant dermatologist, Max Healthcare, nut allergies are very much part of this trend.
Typically, nut allergies cause noticeable reactions on the skin. The allergy would present itself as very itchy reddish dry or oozy eruptions, mainly on the limbs or face. According to Ashutosh Shukla, consultant, internal medicine, Artemis Health Institute, reactions can vary from skin reactions to gastrointestinal problems that include belly cramps, nausea, vomiting or diarrhoea. It could also cause respiratory problems—a sneezing bout, for instance. It could even affect the cardiovascular system, causing anaphylaxis—a condition in which airways swell and blood pressure drops.
Allergy tests
These are now commonly available. According to Dr Giridhar, “The allergies can be diagnosed by testing blood for specific immunoglobinE (an antibody that blood makes in response to an allergen) levels against a particular allergen or by doing skin-prick tests.”
Living with the condition
Most people have to live with the allergy. “Desensitization has been tried but as far as I know it’s not very successful and generally, the person has to live with it,” says Dr Giridhar. Unfortunately, for most people, the only way out is to avoid nuts. It’s easier said than done as this includes avoiding any food stuff manufactured in a facility that uses nuts in any form—to guard against cross-contamination. Be especially wary of candies, cookies and ice creams, warns Dr Shukla. Often, peanut or peanut butter is used to thicken chilli and other sauces. In the West, stringent food labelling laws ensure fewer risks. In India, while companies are gradually becoming sensitive to the issue, it’s still a case of trial and error for sufferers.
Anyone diagnosed with a life-threatening peanut or tree nut allergy (or any kind of life-threatening food allergy) should carry an epinephrine auto-injector for an emergency. Dr Shukla says that it’s also a good idea to carry an over-the-counter antihistamine as this can help treat mild allergy symptoms. Use antihistamines in addition to — not as a replacement for — the epinephrine shot in life-threatening situations.
(Write to us at businessoflife@livemint.com)
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First Published: Thu, May 22 2008. 11 09 PM IST