A near-complete food
Grains are also unique as a food. In botany, they are classified as "fruit seeds", meaning the fruit and the seed are fused or combined into one. They are different from regular fruits that have a skin, a layer of flesh and separate seeds.
The Nutrient Composition of Whole Grains
Whole grains are the means by which plants reproduce. They therefore contain all the major nutrients and elements - carbohydrates, protein, oils, vitamins, minerals, fibre and phytonutrients - that are essential for new plants to grow. Grains are fit for human consumption provided we eat them whole. Refined grains are "empty foods" that provide mainly calories and little else. Such refined grains or flours are basically starches.
The Limitations of Grains in Human Nutrition
Plant food is generally incomplete for humans, however. And grains have two limitations:
- Grains do not contain much protein (typically 10 to 15 percent) and its protein does not include all the eight essential amino acids. Lysine is usually missing from grains but abundant in many legumes. At the same time, legumes tend to be deficient in methionine, which grains contain. Instinctively, traditional diets combine grains with legumes to balance their essential amino acids. Typical combinations include:
- Rice with lentils in South India;
- Wheat with lentils in North India and Pakistan;
- Rice with tofu and fermented soy products (which are complete proteins) in China;
- Corn with beans in Central America.
- Grains are low in fats (typically less than 2 percent) and the essential fatty acid is primarily omega-6, while omega-3 is absent. To achieve a balanced ratio of omega-6 to omega-3, grains must be eaten with foods that are rich in omega-3, such as wild seafood or free-range eggs.
Enhancing Grain-based Diets for Optimal Nutrition
You will therefore not obtain optimal nutrition from eating just grains. What you will get are the basic nutrients needed for survival. Yet whole grains come closer to being a complete food than if you were to eat only vegetables, fruits, nuts or legumes.
This content is adapted, with permission, from Book 1 of 2 : The Wonders of Nutrition by Dr Ang Poon Liat. MBBS, M.MED (PAED), MRCP (UK PAED), FAMS, MD.