Goitre is the abnormal enlargement of the thyroid gland due to iodine deficiency. When iodine is insufficient, the thyroid cannot produce adequate hormones. The pituitary gland secretes excess TSH (Thyroid Stimulating Hormone) to stimulate the thyroid, causing it to enlarge. Iodized salt is the most effective and economical prevention strategy for goitre.

A Calorie (kcal - kilocalorie) is a unit used to measure the energy content of food. Technically, 1 kcal = the energy needed to raise 1 kg of water by 1 degree C. In nutrition, 'Calorie' (with capital C) = 1 kilocalorie. Energy values: Carbohydrates = 4 kcal/g, Proteins = 4 kcal/g, Fats = 9 kcal/g, Alcohol = 7 kcal/g.

Soybean is the richest plant source of protein, containing approximately 36-40g of protein per 100g (dry weight). It is also a complete protein - containing all 9 essential amino acids - making it unique among plant foods. Soy products like tofu, tempeh, and soy milk are excellent protein sources for vegetarians. Soybean also contains omega-3 fatty acids and isoflavones.

Glycogen is the storage form of glucose in the human body. It is stored mainly in the liver and muscles. Liver glycogen maintains blood glucose levels between meals. Muscle glycogen provides energy during exercise. Plants store glucose as starch, not glycogen. When glycogen stores are full, excess glucose is converted to fat.

Vitamin D is called the Sunshine Vitamin because it is synthesized in the skin upon exposure to UV-B rays from sunlight. Sunlight converts 7-dehydrocholesterol in the skin into Vitamin D3 (Cholecalciferol). This is then converted to its active form Calcitriol in the liver and kidneys. People with limited sun exposure are at high risk of Vitamin D deficiency.

Hypervitaminosis A is caused by excess intake of Vitamin A. Symptoms include headache, nausea, liver damage, bone pain, hair loss, and blurred vision. In pregnant women, excess Vitamin A is teratogenic (causes birth defects). Since Vitamin A is fat-soluble, it accumulates in liver and fatty tissues. Toxicity does NOT occur from beta-carotene (plant form) as conversion is regulated.

Magnesium (Mg) is a cofactor for over 300 enzymatic reactions in the body. Its functions include: Muscle and nerve function, Protein synthesis, Blood glucose regulation, Blood pressure regulation, Bone formation (60% stored in bones), and Energy production (ATP activation). Deficiency causes muscle cramps, tremors, insomnia, and cardiac arrhythmias. Rich sources: nuts, seeds, whole grains, leafy greens.

The main functions of fats in the body include: Energy storage (9 kcal/g - most energy-dense), Insulation - subcutaneous fat maintains body temperature, Protection of vital organs (cushioning), Absorption of fat-soluble vitamins (A, D, E, K), Synthesis of hormones (steroid hormones, Vitamin D), and Cell membrane structure (phospholipids).

Anorexia Nervosa is a serious eating disorder characterized by self-starvation, extreme restriction of food intake, intense fear of weight gain, and distorted body image. It leads to severe malnutrition, electrolyte imbalances, bone loss, heart problems, and can be fatal. Bulimia Nervosa (binge-purge cycle) and Binge Eating Disorder are other eating disorders. These are complex psychological conditions requiring professional treatment.

Trans fats (Trans Fatty Acids) are artificially produced by partial hydrogenation of vegetable oils (found in margarine, vanaspati, packaged snacks). They are the most harmful dietary fats because they raise LDL (bad cholesterol) and lower HDL (good cholesterol), significantly increasing risk of heart disease, stroke, and type 2 diabetes. WHO has called for global elimination of trans fats.