Don't you need collagen and animal fat from animals?

The objection

“Skin, joints, bones, they’re built from collagen, and collagen only comes from animals. Plants have none, so vegans must miss out.”

The answer

This rests on a tidy-sounding idea that the digestive system simply doesn’t honour.

It’s true that collagen is an animal protein and plants contain none. But eating collagen doesn’t deliver collagen to your skin any more than eating a heart strengthens yours. The gut breaks dietary protein, collagen included, down into individual amino acids, which enter a shared pool. Your body then builds its own collagen from scratch, assembling it from amino acids like glycine, proline and lysine, all readily available from plant protein.

The genuine rate-limiting factor is vitamin C, the essential cofactor your cells need to lock proline and lysine into a stable collagen structure. Pre-made collagen has nothing to do with it. Plant diets tend to be rich in vitamin C, which is one reason scurvy, the disease of collapsed collagen, is a vitamin C deficiency rather than a “didn’t eat enough connective tissue” deficiency. Get adequate protein and vitamin C and the body manufactures all the collagen it needs.

The same logic dispatches “animal fat.” No fat your body strictly requires comes only from animals. There are just two essential fatty acids, an omega-6 (linoleic acid) and an omega-3 (alpha-linolenic acid), and both are plant fats, abundant in seeds, nuts and oils. Saturated animal fat is not an essential nutrient. It’s the fat health bodies advise eating less of.

The defensible claim: collagen and animal fat are things the body either makes itself or doesn’t require at all. The raw materials are amino acids and vitamin C, and plants hand over both.