(M. Noman*, Mujahid Ali**, Dr. Zahoor Hussain**)
(*IFSN, UOS; **Horticulture, UOS)
Walnut is delicious fruit eaten as dried fruit. It is used throughout world processing industry. Its world production is 3.46 million tons. Its leading producers are China, United States, Iran, Turkey, Mexico. China is producing 46 percent of total world production. California is producing 99 percent of walnut of United States. In Pakistan its production is low, so it is considered as minor fruit. It has a history of Chinese culture, moreover in Pakistan children play with this fruit. Its fruit is called a nut because of its hard-outer shell. It can be added to chicken and fish during cooking in shredded form. It is processed in juices and in yogurt to make a tasty dessert. It is among those fruits which are not perishable.
Walnuts are a rich source of energy and hold many health-benefiting nutrients, minerals, antioxidants, and vitamins that are essential for wellbeing. They are a rich source of monounsaturated fatty acids (approximately 72%) like oleic acid and an excellent source of all-important omega-3 essential fatty acids such as linoleum acid, alpha-linolenic acid (ALA) and arachidonic acids. Regular consumption of walnuts in the diet, therefore, may help in lowering total as well as LDL or “bad cholesterol” and increases HDL or “good cholesterol” levels in the blood. Research studies suggest that the Mediterranean diet which is rich in mono-unsaturated fatty acids and omega-3 fatty acids may help cut-down chances of coronary artery disease, and strokes by favoring healthy blood lipid profile. It is helpful in the prevention of cancer (skin cancer) having lot of antioxidants. It improves heart function, male fertility, weight management, brain health, metabolism and reduces inflammation. It has a positive effect on hair growth. In pregnant women these help in fetal growth.
Eating as just as a handful (25 g) of walnuts every day can provide about 90% of RDI (recommended daily intake) of omega-3 fatty acids. Research studies suggest that n-3 fatty acids by their anti-inflammatory actions may help lower blood pressure, cut down coronary artery disease and stroke risk, and offer protection from breast, colon and prostate cancers.
Additionally, they are a rich source of many photochemical substances that may contribute to their overall antioxidant activity, including melatonin, ellagic acid, vitamin-E, carotenoids, and polyphenolic compounds. These compounds are known to have potential health effects against cancer, aging, inflammation, and neurological diseases.
Scientists at the University of Scranton, Pennsylvania, had recently found that walnuts possess the highest levels of polyphenolic antioxidants of all the edible seeds and nuts. 100 g of the nuts carry 13,541 µmol TE (Trolox equivalents) of oxidant radical absorbance capacity (ORAC). Eating as many as six to seven walnuts a day could help stave off most of the disease-causing free radicals from the human body.
Further, they are an excellent source of vitamin-E, especially rich in γ -tocopherol; carry about 21 g per 100 g (about 140% of daily required levels). Vitamin-E is a powerful lipid soluble antioxidant essential for maintaining the integrity of cell membrane of mucosa and skin by protecting it from harmful oxygen-induced free radicals.
They are also packed with several important B-complex groups of vitamins such as riboflavin, niacin, thiamin, pantothenic acid, vitamin B-6, and folates.
They also very are a rich source of minerals such as manganese, copper, potassium, calcium, iron, magnesium, zinc, and selenium. Copper is a cofactor for many vital enzymes, including cytochrome C-oxidize and superoxide dismutase (other minerals function as co-factors for this enzyme are manganese and zinc). Zinc is a co-factor in growth and development, gonad development, digestion, and nucleic acid synthesis.
But eating too much walnut is harmful as it causes allergic reactions, lip cancer, tongue swelling, sometimes body produces rashes and swelling, diarrhea, nausea, lip cancer, asthma, acne, and ulcer etc.