Anti Nutrients

Anti Nutrients

Subject: Science & Tech

Section: Basic

Context- Improving natural iron absorption from iron­rich grains is a better strategy than chemical iron fortification of cereals.

Concept-

Iron Deficiency In India:

• The iron deficiency occurs less likely due to an iron ­deficient diet, and more likely due to poor absorption of dietary iron.
• With poor, cereal based diets, iron is not well absorbed, because of a substance called phytate that is present in cereal grains, which binds tightly to dietary iron and impedes its absorp­tion.
• Similarly, drinking tea or taking paan after meals al­so blocks iron absorption be­cause of other inhibitory substances called polyphe­nols, which also bind iron tightly.
• Chronic body inflam­mation also blocks iron ab­sorption from the intestine.
• This iron absorption blockade can be overcome by eating fruits (vitamin C) with meals, or simply chang­ing behavior, like avoiding tea with meals.

Millets for Iron Deficiency:

• Alternatively, dietary iron intake could be increased in a natural man­ner, by eating iron rich grains like millets, which will increase iron intake natural­ly, and not excessively.
• It is laudable that there is interest in promoting millet con­sumption in India for adults and children: these ancient grains are good for us in many ways, and not just for their rich iron content.
• They are also high in calcium, zinc, magnesium, potassium, dietary fibre, and important vitamins such as thiamine, riboflavin, folic acid, and niacin.

About Anti- Nutrients:

• The term “anti-nutrients” suggests what they are.
• Whereas nutrients are substances that nourish plants and animals to grow and live, anti-nutrients earn their title because they can block the absorption of nutrients.
• Anti-nutrients are naturally found in animals and many plant-based foods.
• In plants, they are compounds designed to protect from bacterial infections and being eaten by insects.
• There are several compounds in the foods we eat classified as anti-nutrients. Examples include:
  • Glucosinolates and goitrogens in cruciferous vegetables (broccoli, Brussels sprouts, cabbage, kale)—can prevent the absorption of iodine, which may then interfere with thyroid function and cause goiter. Those already with an iodine deficiency or a condition called hypothyroidism are most susceptible.
  • Lectins in legumes (beans, peanuts, soybeans), whole grains—can interfere with the absorption of calcium, iron, phosphorus, and zinc.
  • Oxalates in green leafy vegetables, tea, beans, nuts, beets—can bind to calcium and prevent it from being absorbed.
  • Phytates (phytic acid) in whole grains, seeds, legumes, some nuts—can decrease the absorption of iron, zinc, magnesium, and calcium.
  • Saponins in legumes, whole grains—can interfere with normal nutrient absorption.
  • Tannins in tea, coffee, legumes—can decrease iron absorption.