Proteins

These, plus water, are what we are mostly made of. They are complex chemical products built up from amino acids – twenty of them in human beings, of which adults require eight in their diet, growing children one or two extra ones. The rest are produced inside our bodies. The proteins that we eat have to be broken down into their constituent amino acids, and used again in the construction of bone, muscle, blood, skin, and so on. Plant proteins are almost all incomplete – missing a few vital amino acids. Vegetarians can thrive, however, by eating plants whose proteins are complementary: they make up for each other’s deficiencies. Many Javanese people who cannot afford much meat live on rice and soya beans, whose proteins complement each other very effectively.