There is a growing trend of eating more vegetables and less meat. However, different vegetables contain different nutrients. Fion CHOW, accredited Practising Dietitian (DAA, AUS) and Assistant Treasurer of Hong Kong Dietitians Association, suggests a series of ways to cook and store vegetables to reap their maximum nutritional benefits.

Table 1 : Functions and Nutritional Values of Different Types of Vegetables

Nutrients or Phytochemicals	Functions
Dietary Fibre	Dietary fibre is the indigestible part found in plant. Although dietary fibre cannot be absorbed by human body, it plays an important role in our health. It stimulates bowel movement and maintains gastrointestinal health.
Beta-carotene	Beta-carotene can be converted into vitamin A upon body absorption. Vitamin A is essential for the health of eye, skin and mucus membrane.
Folic Acid	Folic acid helps prevent anaemia. Some studies showed that adequate consumption of folic acid can reduce the risk of heart disease.
Vitamin C	Vitamin C helps promote tissue growth and repair, as well as wound healing. It aids the absorption of iron. Vitamin C deficiency may lead to scurvy.
Potassium	Potassium is essential in maintaining electrolyte balance and cellular function in our bodies. Adequate potassium intake can lower blood pressure.
Magnesium	Magnesium plays an important role in maintaining bone health. It is known that over 50% of magnesium in human body is stored in bones.
Phytochemicals	Plants produce 'phytochemicals' to protect themselves against micro-organisms like bacteria and fungi. Phytochemicals were found to have antioxidant effect in most cases and are believed to be conducive to health improvement and illnesses reduction.

Some of the root vegetables are relatively rich in carbohydrates. For instance, 100g of lotus root contains about 20g of carbohydrates. Legumes like soybeans and red beans, which contain higher amounts of protein (Table 3), are meat alternatives. Soybeans contain about 20% fat, and it is mainly unsaturated fat, which is particularly good for cardiovascular functions. Mushrooms like white button mushroom and enokitake mushroom contain higher amounts of dietary fibre.

Fion added, vegetables are generally low in sodium but are high in potassium (Table 3). A low sodium and high potassium diet helps maintain normal blood pressure, hence reducing the risk of cardiovascular diseases.

Diagram 1: Nutritional Values of Different Types of Vegetables

Some of the Root Vegetables (Lotus roots, sweet potatoes, taros, etc.) Some root vegetables have higher amounts of carbohydrates, hence the higher amounts of calories.

All Types of Vegetables Provide dietary fibre, beta-carotene, folic acid, vitamin C, potassium, magnesium and phytochemicals. Mushrooms (straw mushrooms, shiitake mushrooms, king oyster mushrooms, white king oyster mushrooms, etc.) Mushrooms are rich in dietary fibres.

Legumes (Red beans, soybeans, black eyed peas, etc.) Legumes, containing higher amounts of protein, are meat alternatives.