Vitamins

The first vitamin (Vitamin A) was identified in 1913, marking a significant milestone in nutrition science.
Initially, the belief was that diseases were mainly caused by germs, and food was primarily considered a combination of proteins, carbohydrates, fats, and minerals.
Unit topics related to vitamins include:
- Functions of vitamins in the body.
- Food sources of vitamins.
- Health consequences of both toxicity and deficiency for at least two key vitamins.

Vitamins are essential nutrients required by the human body that perform specific and critical functions.
There are fourteen recognized vitamins, and deficiency diseases can develop if there is inadequate vitamin intake over time.

These include the B-complex vitamins (such as B1, B2, B3, and others) and vitamin C.
They are easily absorbed by the body but cannot be stored in significant amounts, necessitating regular consumption to avoid deficiencies.
Excess amounts are typically excreted in urine, making overdoses uncommon but still possible under rare circumstances, especially with supplements.

This group includes vitamins A, D, E, and K.
Fat-soluble vitamins are soluble in fat, meaning they can be stored in the body’s fatty tissues and the liver for extended periods.
However, because they accumulate, they can reach toxic levels if consumed excessively, particularly via supplements or fortified foods.
They are primarily found in fat-containing foods such as dairy products, oils, nuts, and fatty fish.

Vitamins do not directly provide energy but are crucial coenzymes that play vital roles in converting food into energy for bodily functions.
They are essential for building and maintaining various tissues and health at the cellular level.
Certain vitamins, particularly from the B-complex group, assist in hormone production and may also influence behaviors; deficiencies can result in irritability, anxiety, and poor appetite.

Vitamin A: Critical for vision (particularly night vision), supports immune function, and facilitates cell differentiation. Deficiency can lead to compromised immune response and night blindness. Toxicity can cause severe health issues, including liver damage and headaches.
Vitamin D: Essential for bone health, aids in calcium and phosphorus absorption, and can improve muscle function. It can be synthesized by the body when exposed to sunlight, but dietary sources include fatty fish, fortified milk, and egg yolks. Deficiency may result in rickets in children and osteomalacia in adults.
Vitamin E: Acts as a powerful antioxidant, protecting cells from oxidative damage, and is crucial for the development of nerves and muscles. Deficiency is rare but can hinder immune response.
Vitamin K: Plays a vital role in blood coagulation and is essential for maintaining bone health. There are two forms: K1 (found in leafy greens) and K2 (found in fermented foods). Deficiency can lead to excessive bleeding and weakened bones.

Thiamin (B1): Essential for carbohydrate metabolism, serving as a coenzyme in energy production; deficiency leads to beriberi, which affects cardiovascular and nervous systems.
Riboflavin (B2): Acts as an antioxidant; also plays a role in energy production and the metabolism of fats, drugs, and steroids. Deficiency causes ariboflavinosis, resulting in sore throat and cracks near the corners of the mouth.
Niacin: Necessary for the metabolism of carbohydrates and fats; deficiency results in pellagra, characterized by dermatitis, diarrhea, and dementia.
Folate: Crucial for DNA synthesis and cell division; deficiency can lead to neural tube defects in embryos, highlighting its importance for pregnant women.
Vitamin B12: Important for maintaining nerve cells and red blood cell formation; deficiency can result in pernicious anemia, characterized by fatigue and nerve damage.

Vitamins can be easily destroyed or reduced in potency due to various factors:
- Air Exposure: Certain vitamins, especially water-soluble ones, are sensitive to oxidation; minimizing cutting and handling prior to cooking can help preserve these nutrients.
- Water Soaking: Soaking fruits and vegetables can leach out water-soluble vitamins; it is advised to cook with minimal water to retain nutrients.
- Heat: Cooking methods that involve high heat can destroy water-soluble vitamins, particularly vitamin C; quick cooking methods such as steaming or microwaving are recommended to minimize nutrient loss.
- Storage: Keeping produce refrigerated and consuming it quickly can help maintain vitamin content. It's also beneficial to store fruits and vegetables in a way that minimizes exposure to air and moisture to reduce degradation of vitamins.