Prevent deficiency disease

A full stomach says nothing about vitamins and minerals. The field measure is dietary diversity: ask a woman of childbearing age what she ate yesterday, and count how many of these 10 groups appear.

1. Grains, white roots and tubers
2. Pulses — beans, peas, lentils
3. Nuts and seeds
4. Milk and milk products
5. Meat, poultry and fish
6. Eggs
7. Dark green leafy vegetables
8. Other vitamin A-rich fruit and vegetables — orange flesh: carrot, pumpkin, mango, orange sweet potato
9. Other vegetables
10. Other fruit

Five or more groups is FAO's threshold (the MDD-W indicator) for a diet likely to meet micronutrient needs. Women are counted because pregnancy and breastfeeding raise their needs most, so a diet that passes for them usually passes for the household.

Count again at the end of winter. Stores narrow the diet to grain, and that is when deficiency starts.

Maize holds its niacin (vitamin B3) in a bound form the gut cannot release, and is poor in tryptophan, from which the body makes niacin. A population living on untreated maize gets pellagra: a symmetrical, sharp-edged rash on skin the sun reaches — backs of the hands, forearms, a band round the neck — then diarrhoea, then confusion and dementia, then death. Cases rise in spring, after a winter on stored maize.

Nixtamalise — the Mesoamerican method, in use for about 3,000 years:

1. Per 1 kg of dried maize: 3 litres of water and 10 g of slaked lime (calcium hydroxide) — 1% of the grain's weight. Without lime, use hardwood-ash lye: stir ash into water, let it settle, and use the clear liquid. Its strength varies, so judge it by the next step.
2. Simmer 20–40 minutes, stirring, until the skin of a test kernel rubs off between finger and thumb.
3. Cover and steep 8–16 hours.
4. Drain and rinse in several changes of water, rubbing, until the water runs clear and the kernels no longer feel slippery.
5. Grind wet to dough, or cook whole as hominy.

Eat beans with maize. Beans supply the tryptophan maize lacks; maize, beans and squash together is the diet that did not produce pellagra.

Thiamine (vitamin B1) sits in the bran and germ, which milling removes: white rice has lost most of its thiamine. The body holds only about 25–30 mg — a few weeks' supply — so a diet of polished rice produces beriberi:

• Dry beriberi — numb, weak legs and a stumbling walk.
• Wet beriberi — swollen legs, breathlessness, a failing heart.
• Infantile beriberi — in breastfed babies of deficient mothers, usually at 2–6 months: a hoarse or silent cry, vomiting, fast breathing. It can kill within hours.

Parboiling drives the thiamine into the grain while it is still in the husk:

1. Soak the paddy — rice still in its husk — overnight in cold water, or 3–4 hours at 60–70 °C: too hot to hold a hand in, well short of boiling.
2. Drain and steam 10–20 minutes, until a few husks split.
3. Dry in a thin layer, turned often, down to about 14% moisture. Drying too fast in strong sun cracks the grains.
4. Mill as usual. Parboiled rice keeps more thiamine through milling and breaks less.

Or mill lightly and eat the rice brown. Either way, do not wash rice repeatedly or pour away its cooking water — thiamine dissolves into it. Pulses and groundnuts eaten with rice supply thiamine too.

The body cannot make vitamin C and holds about 1,500 mg. With none in the diet, scurvy appears within about 1–3 months: tiredness and aching legs, then gums swollen, dark and bleeding, bruising at a touch, pinpoint bleeds around the hair follicles of the legs, old wounds reopening, then death. About 10 mg a day prevents it; aim for 50–100 mg for margin.

Vitamin C per 100 g, approximately:

• Rose hips, fresh: over 400 mg
• Blackcurrants: about 180 mg
• Kale, raw: about 90–120 mg
• Lemon juice, fresh: about 40 mg
• Cabbage, raw: about 35 mg
• Sauerkraut: about 15 mg
• Mung bean or lentil sprouts, 2–4 days old: about 13–17 mg
• Potatoes, boiled in their skins: about 13 mg
• Dried grain, dried beans, dried or salted meat: almost none

Heat, air, time and copper destroy it. Eat greens raw where they have been washed in safe water; cook briefly in little water and drink the water; never store juice in copper.

Sprout seed in late winter: soak dried peas, beans or lentils 8–12 hours, drain, rinse twice a day in safe water, and eat raw at 2–4 days — the sprouting seed makes vitamin C the dry seed lacks. 100 g a day of sauerkraut, potatoes or sprouts covers the minimum through the hungry gap.

Treat scurvy the same day with the richest raw source available. The gums improve within days.

Glaciation, heavy rain and flooding wash iodine out of soil, so inland, mountain and river-valley settlements grow food short of it; coastal diets rarely are. Adults need about 150 µg a day, 250 µg in pregnancy.

• Goitre — a soft swelling at the front of the neck that rises when the person swallows. It shows the population is short.
• Deficiency in pregnancy is the serious harm: stillbirth, and cretinism — permanent intellectual disability, deafness and stunting in the child. WHO calls iodine deficiency the world's leading preventable cause of brain damage.

A goitre in more than 5% of schoolchildren (WHO's threshold) marks the whole settlement as iodine-poor.

Sources, most reliable first:

• Sea fish and shellfish, eaten weekly.
• Kelp (kombu) — commonly 1,000–3,000 µg per gram dried, and highly variable, so about 1 g a week covers an adult. The thyroid stores iodine, so weekly intake is enough. Wakame and nori carry far less.
• Iodised salt, once iodine can be made or traded: 20–40 mg of iodine per kg of salt (WHO range). Switzerland began iodising salt in 1922, and endemic cretinism there disappeared.

Vitamin D is made in skin by midday sun. Beyond about 35–37° latitude, north or south, the winter sun is too low to make any for several months. Children in cold climates, children kept indoors or fully wrapped, and dark-skinned children at high latitude get rickets: soft bones, legs that bow once walking starts, a row of knobs down the ribs, late walking. Girls with rickets grow a narrowed pelvis, which made obstructed labour common a generation later.

• Summer: arms and face in midday sun 5–30 minutes, two or three times a week for pale skin, several times longer for dark skin. Stop before the skin reddens.
• Winter and high latitude: oily fish two or three times a week, and eggs.
• Cod-liver oil works, with a limit. One 5 ml teaspoon carries about 11 µg of vitamin D — a child needs 10–15 µg a day — but also about 1,350 µg of vitamin A, against an upper limit of 600 µg a day for a child under 4. Give small children no more than half a teaspoon, and none on days they eat liver.

Vitamin A is stored in the liver, so deficiency comes slowly, then fast:

1. Night blindness — a child who cannot see at dusk when others can. This is the sign to act on.
2. Dry, dull whites of the eye, with foamy grey patches (Bitot's spots).
3. Softening of the cornea, then permanent blindness.

Deficiency also raises deaths from measles and diarrhoea: correcting it in deficient populations cuts child deaths by roughly 12–24%. Sources: liver (a small portion once a week is plenty), eggs and milk fat, and orange and dark green plants — carrot, orange sweet potato, pumpkin, mango, dark leaves, red palm oil. Plant carotene needs fat in the same meal to be absorbed.

Malnutrition kills most between 6 months and 2 years, when breast milk stops being enough on its own and the food added to it is too thin. A small child eats about 30 g per kg of body weight at a meal. A watery gruel carries 0.3–0.4 kcal per gram; a child needs food nearer 0.8–1 kcal per gram to meet its needs in the meals it can hold.

• Breastfeed alone to 6 months, then keep breastfeeding to 2 years alongside food.
• From 6 months, porridge thick enough to stay on a tilted spoon — not a gruel that runs off it.
• Thicken with energy, not water: stir a spoon of oil or fat, mashed pulses, groundnut paste, egg or fish into every meal.
• Malted flour lets porridge be thick and still swallowable: sprout grain 1–2 days, dry it and grind it, and stir a pinch into cooked thick porridge. Its enzymes thin it without adding water.
• Meals: 2–3 a day at 6–8 months, 3–4 a day at 9–23 months, plus 1–2 snacks.

Measure the arm. Mark a strip of cloth at 11.5 cm and 12.5 cm, and wrap it round the middle of the left upper arm of every child aged 6 months to 5 years, monthly:

• Under 11.5 cm, or swelling of both feet — severe acute malnutrition, a medical emergency.
• 11.5–12.5 cm — moderate: enrich every meal and measure again at the next check.
• Over 12.5 cm — adequate.

Deficiencies come together, in the same people and the same season. Once a year, when stores are lowest, look for these and answer each with food that day:

• Bleeding, swollen gums; bruising; pinpoint bleeds on the shins — vitamin C: raw greens, sprouts, sauerkraut, fruit, daily.
• A sharp-edged rash on the backs of the hands, forearms or neck; diarrhoea — niacin: nixtamalised maize, beans, groundnuts, meat, fish.
• Numb or weak legs, swollen legs, breathlessness — thiamine: parboiled or brown rice, pulses, groundnuts.
• A child who cannot see at dusk; dry, dull whites of the eye — vitamin A: liver, egg, orange or dark green plants eaten with fat.
• A toddler's legs bowing; late walking — vitamin D: midday sun, oily fish, egg.
• A neck swelling that rises on swallowing — iodine: sea fish, measured seaweed, iodised salt.
• Pale inner eyelids, breathlessness, exhaustion — iron: meat, liver, pulses eaten with vitamin C; no tea with meals, which blocks absorption.
• An upper arm under 12.5 cm, or swollen feet, in a young child — energy and protein: thick enriched porridge. Under 11.5 cm, or both feet swollen, is an emergency.

For treatment beyond food — doses, and the severe cases — use a current manual such as Hesperian's Where There Is No Doctor.