People adhere to vegetarian diets for many reasons, mostly related to religion and belief, health benefits, environmental issues, and even aesthetic and economic reasons.

There are different types of vegetarian diets, largely defined by the dietary restrictions that are imposed:

-- Vegan (total vegetarian): No meat, poultry, fish or any products from animals, including eggs, milk and dairy products and gelatine.

In Asia, a typical vegan also avoids onion and garlic.

-- Lacto-ovo vegetarian: No meat, poultry and fish, but eggs and dairy products are allowed.

-- Lacto-vegetarian: No meat, poultry, fish or eggs, but can consume dairy products.

-- Ovo-vegetarian: No meat, poultry, fish or dairy products, but can eat eggs.

--Partial vegetarian: Pesco-vegetarians/Pescetarians avoid meat and poultry, but may eat fish, and pollo-vegetarians avoid meat and fish, but may eat poultry.

Some vegetarians rely too heavily on processed foods, which can be high in calories, sugar, fat and sodium.

Ironically, they may not eat enough fruits, vegetables, whole grains and calcium-rich foods, thus missing out on the nutrients they provide.

According to the American Dietetic Association, "Appropriately planned vegetarian diets, including total vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases."

The key word here is "appropriately planned". There are vegetarian guidelines you can follow or you may consult a dietitian for a properly-planned vegetarian diet to help ensure you or your family will not miss out on important nutrients.

Vegetarians need to be mindful of some particular nutrients:

Protein: This helps maintain healthy skin, bones, muscles and organs.

Lacto-ovo diets, which include eggs and dairy products, can easily meet the daily requirement for protein.

However, for a vegan, the source of protein has to come from other plant sources, such as soy and soy products, legumes, lentils, nuts, seeds and whole grains.

Iron: This is a crucial component of red blood cells.

Dried beans and peas, lentils, enriched cereals, whole grain products, dark leafy green vegetables, and dried fruit are good sources of iron.

Because iron isn't as easily absorbed from plant sources, the recommended intake of iron for vegetarians is almost double that recommended for non-vegetarians.

To help your body absorb iron, eat foods rich in vitamin C, such as strawberries, citrus fruits, tomatoes, cabbage and broccoli, at the same time you are eating iron-containing foods.

Zinc: This mineral is not as easily absorbed from plant sources as it is from animal products.

Zinc is an essential component of many enzymes and plays a role in cell division and the formation of proteins.

Cheese is a good option if you eat dairy products.

Plant sources of zinc include whole grains, soy products, legumes, nuts and wheat germ.

Vitamin B12: This vitamin is necessary to produce red blood cells and prevent anaemia.

It is found almost exclusively in animal products, so it can be difficult to get enough this vitamin in a vegan diet.

Vitamin B12 deficiency may go undetected in people who eat a vegan diet.

This is because the vegan diet is rich in a vitamin called folate, which may mask deficiency in vitamin B12 until severe problems occur.

For this reason, it's important for vegans to consider vitamin supplements, vitamin-enriched cereals and fortified soy products.

Calcium and vitamin D: Calcium helps build and maintain strong teeth and bones. Milk and dairy foods are highest in calcium.

However, dark green vegetables, like turnip, collard greens, kale and broccoli, are good plant sources when eaten in sufficient quantities.

Calcium-enriched and fortified products, including juices, cereals, soy milk, soy yogurt and tofu, are other options.

Vitamin D also plays an important role in bone health.

It is added to cow's milk, some brands of soy and rice milk, and some cereals and margarines.

Exposure to sunlight is also a means of acquiring vitamin D. Exposing yourself to sunlight at least 30 minutes each day will help you get sufficient vitamin D.

However, if you don't eat enough fortified foods and have limited sunlight exposure, you may need a vitamin D supplement (one derived from plants).

Omega-3: These fatty acids are important for heart health.

Diets that do not include fish and eggs are generally low in the active forms of omega fatty acids such as EPA and DHA.

The body can convert ALA in plant foods to EPA and DHA. Canola oil, soy oil, walnuts, ground flaxseed and soybeans are good sources of this essential fatty acid.

Vegans can also get DHA from algae/algae supplements.

Myths and facts about vegetarian diets

A vegetarian diet is good for weight loss

Even though a typical vegetarian diet avoids animal meat and products, foods such as vegetarian pizza, deep fried soy products and many artificial mock meats eaten by some vegetarians might be high in fat, carbohydrates and calories.

Overweight or weight problems isn't about whether you are vegetarian or not, it's more about the total calories that you take and the energy output from your physical activities.

Some beans and nuts are higher in fats. Hence, a small handful of these are good sources of protein and fats.

Always be mindful of portion size and cooking methods. Do read food labels to understand how much you have taken in terms of calories and nutrients based on a serving size.

A vegetarian diet is healthier compared to a non-vegetarian one

Vegetarians tend to consume less saturated fat and cholesterol, but more dietary fibre, potassium, magnesium and phytochemicals from plant sources that are good for heart protection.

Some evidence shows that vegetarians have a 19%-25% lower risk of cardiac related deaths compared to non-vegetarians.

In addition, many studies have shown that taking more fruits and vegetables helps in cancer prevention and there is some evidence that shows that a vegetarian has lower incidence of cancer compared to non-vegetarians.

However, there are some studies that show that avoiding red meat, but including fish in the diet can reduce the risk of certain cancers compared to a vegetarian diet (Oxford Vegetarian Study).

Plant-based vegetarians also reduce the risk of developing type 2 diabetes by half (compared to non-vegetarians with the same body mass index).

Copyright: The Star Online/ Asia News Network