Antioxidants
High intakeNeutralise free radicals, lower oxidative stress & chronic inflammation, support arteries, brain & skin. Best sources: berries, dark chocolate, spices (turmeric, oregano, cinnamon), beans, dark leafy greens, walnuts, EVOO.
Low intakeMore oxidative damage, faster vascular aging, higher chronic-disease risk. Common in low-plant diets.
AffectsHeart & arteries, brain, skin, eyes, immune system.
Calcium
High intakeBuilds & maintains bones and teeth, supports muscle contraction, blood clotting & nerve signaling. Modestly lowers blood pressure (the dairy arm of DASH). Best sources: milk & yogurt, sardines with bones, tofu, dark leafy greens (ewedu, ugu, spinach), almonds, chia, sesame.
Low intakeBone loss (osteopenia, osteoporosis, higher fracture risk), muscle cramps, weaker BP control. The body steals calcium from bone to keep blood levels normal, so deficiency stays silent until bones are already weakened.
AffectsBones & teeth, muscles, heart rhythm, blood pressure, nerves, blood clotting.
Calories
High intakeMore energy in than the body burns — the surplus is stored as fat. Excess weight then feeds into blood pressure (roughly 1 mmHg per kg), insulin resistance, joint load and sleep apnoea. Calorie density is mostly a fat story: fat carries 9 kcal/g against 4 for carbs and protein, so oils, nuts and anything fried climb fastest.
Low intakeA deficit means weight loss — slower than most levers, but durable. Pushed too far below what the body needs, it sheds muscle, energy and nutrient coverage along with the fat.
AffectsBody weight directly; everything else only through weight. Calories are blind to quality — a bouillon cube is ~10 kcal and among the saltiest things on any shelf, while olive oil is 884 kcal and among the best fats for arteries. Rank those two by calories and you get the health answer exactly backwards. Never read this column alone.
Choline
High intakeBuilds cell membranes and makes acetylcholine, the neurotransmitter behind memory, attention and muscle control. Also ferries fat out of the liver, so a shortfall lets fat accumulate there. Especially important in pregnancy for fetal brain development. Best sources: cow liver (426mg), egg (294mg — almost all of it in the yolk), kidney, dried fish, soybeans.
Low intakeFatty liver and raised liver enzymes, muscle damage, and poorer memory and attention. Most people fall short of the target — roughly 425mg a day for women and 550mg for men — largely because egg yolks got avoided for decades over cholesterol that turned out not to matter much.
AffectsBrain & memory, liver, cell membranes, fetal development. The practical point: two whole eggs cover well over half a day’s choline, and there is no comparable plant source — soybeans at 120mg are the best plant option and still less than half an egg’s worth. Egg whites have almost none: this nutrient lives in the yolk.
Cholesterol (dietary)
High intakeThe cholesterol molecule itself — found only in animal foods (egg yolk, offal, shellfish, meat, dairy fat). For most people the liver compensates by making less, so it barely moves blood LDL. But ~1 in 4 are "hyper-responders" (often ApoE4), and it matters far more if you have diabetes, familial hypercholesterolemia, or existing heart disease.
Low intakeNo downside — the body makes all it needs. Plants contain none.
AffectsBlood LDL (mainly in susceptible people), heart & arteries. A weaker lever than saturated fat for most.
Fibre — insoluble
High intakeThe fraction that doesn't dissolve. It passes through largely intact, absorbing water and adding bulk, which speeds transit through the gut. This is the fibre that prevents constipation and keeps the bowel working — mechanical rather than metabolic. Best sources: wheat bran and whole grains, nuts & seeds, vegetable and fruit skins, leafy greens, groundnuts.
Low intakeConstipation, straining, sluggish digestion; long-term shortfall is linked to diverticular disease and poorer bowel health. Refining grain removes the bran, which is where nearly all of it lives — so white rice, white bread, semovita and fufu have very little.
AffectsGut transit and bowel health, plus fullness through sheer bulk. It does not lower cholesterol or blunt blood sugar — that's the soluble fraction's job. Needs water to work: bulk without fluid makes constipation worse, not better.
Fibre — soluble
High intakeThe fraction that dissolves into a gel. It binds bile acids and carries them out, forcing the liver to pull cholesterol from the blood to make more — which is the mechanism behind oats' LDL-lowering reputation. The gel also slows stomach emptying, so glucose enters the blood more gradually, and it ferments in the colon into short-chain fatty acids that feed gut bacteria. Best sources: oats (beta-glucan), beans of every kind, okra and ogbono (the draw is soluble fibre), apples and citrus (pectin), carrots, onions.
Low intakeHigher LDL cholesterol, sharper blood-sugar spikes, poorer gut-bacteria diversity, and less staying power after meals. Most people fall well short of it — it's the harder of the two to hit, which is why its threshold here is set lower.
AffectsCholesterol, blood sugar, gut bacteria, appetite. This is the fraction doing the metabolic work, so it's the one to prioritise for heart and blood-sugar goals — while insoluble fibre handles the plumbing.
Folate
High intakeVitamin B9 — builds DNA and red blood cells, and clears homocysteine from the blood (high homocysteine is an independent risk factor for stroke and heart disease). Critical before and during early pregnancy, where a shortfall causes neural tube defects. Best sources: beans of every kind, dark leafy greens (ewedu, ugu, spinach), avocado, groundnuts, liver, citrus.
Low intakeMegaloblastic anaemia, fatigue, mouth ulcers, raised homocysteine; in pregnancy, serious birth defects. Note that folate leaches into cooking water and degrades with long heat — the greens in a soup keep more of it than the water they were boiled in.
AffectsBlood cells, DNA repair, heart & blood vessels, fetal development.
Fructose
High intakeThe half of sugar that isn't glucose. Every cell in the body can burn glucose — fructose is handled almost entirely by the liver, and once the liver's limit is passed it converts the excess straight into fat. That drives fatty liver, raised triglycerides, insulin resistance and higher uric acid (gout). Concentrated sources: table sugar (50% fructose), honey (~41%), agave, fruit juice, dried fruit.
Low intakeNo downside at all. Fructose is not essential — the body makes every gram of glucose it needs without it.
AffectsLiver (fat accumulation), triglycerides, uric acid & gout, insulin sensitivity. Whole fruit is not the problem — an apple carries ~6g of fructose wrapped in fibre and water, and you'll stop after two. A glass of juice carries the fructose of four apples with the fibre stripped out, and nothing tells you to stop. Same molecule, different delivery. This is also the column glycemic index cannot see: fructose barely moves blood glucose, which is precisely why it scores low and still does damage.
Glycemic index
High glycemic indexCarbs that break down fast — a quick glucose spike, a big insulin response, then a crash that leaves you hungry again. Repeated daily this feeds liver fat and, over years, insulin resistance. White bread, instant noodles, very ripe plantain, potato.
Low glycemic indexSlow, steady glucose release — flatter energy, less insulin, less load on the liver. Beans, unripe plantain, nuts, whole fruit, steel-cut oats.
AffectsBlood sugar, insulin, liver fat, hunger. Two catches: (1) Glycemic index measures speed per gram of carb, not quantity — glycemic load (glycemic index × carb grams ÷ 100) is what a real portion actually does to you. Watermelon is glycemic index 72 but glycemic load ~4, because it's mostly water. (2) Glycemic index is measured on a food eaten alone — adding fat, protein or fibre slows the whole meal down. Shown as "–" for foods with no carbs to speak of (oils, meat, fish).
Iodine
High intakeBuilds thyroid hormones, which set the metabolic rate of every cell. Critical in pregnancy — shortfall is the leading preventable cause of intellectual disability worldwide. Sources are narrow: iodised salt, sea fish, dairy and eggs. Plants only reflect the soil they grew in, and most inland soil has little.
Low intakeGoitre (a swollen thyroid), sluggish metabolism, fatigue, cold intolerance; in pregnancy, permanent harm to the child’s brain development.
AffectsThyroid, metabolism, brain development. The Nigerian angle: universal salt iodisation is why deficiency collapsed here — so cutting salt hard for blood pressure removes an iodine source at the same time. Fish, eggs and dairy cover it without the sodium.
Iron
High intakeCarries oxygen in the blood (haemoglobin) and in muscle (myoglobin), and drives energy production. Two forms behave very differently. Heme iron from meat, offal and fish is absorbed at roughly 15–35% regardless of what else is on the plate. Non-heme iron from beans, greens, seeds and grains is absorbed at only 2–20%, and that figure swings hard on what it's eaten with — vitamin C can multiply it several-fold, while tea, coffee and calcium block it. So a bean dish shows a big number here but delivers far less than the same figure from liver.
Low intakeIron-deficiency anaemia — fatigue, breathlessness, pale skin, poor concentration, weakened immunity. The most common nutrient deficiency worldwide, and heaviest among menstruating women, pregnant women and young children. Adult men need ~8mg a day; menstruating women need ~18mg.
AffectsBlood, energy, immunity, cognition. The practical move: pair plant iron with vitamin C — beans with tatashe or a squeeze of citrus, ugu with fresh peppers — and keep tea or coffee away from the meal rather than with it. One caution: more is not better. The body cannot excrete excess iron, so supplements without a diagnosed deficiency risk overload, and anyone with haemochromatosis should limit it.
Magnesium
High intakeA cofactor in over 300 enzyme reactions — energy production, muscle and nerve function, blood-sugar control, bone structure. It relaxes blood-vessel walls, so along with potassium it's one of the minerals that actively lowers blood pressure. Best sources: pumpkin seeds (592mg), egusi (515mg), brazil nuts, cashews, chia, dark chocolate, beans, leafy greens, oats.
Low intakeMuscle cramps and twitches, fatigue, poor sleep, irregular heartbeat, higher blood pressure, and worse insulin sensitivity. Genuinely common — refining grains strips most of the magnesium out, so diets built on white rice, white bread and cassava run low even when calories are plentiful.
AffectsBlood pressure, muscles & nerves, heart rhythm, blood sugar, bones, sleep. It works with potassium and calcium rather than against them — the three together are the mineral side of the DASH approach, which is why a plate heavy on greens, beans and seeds moves blood pressure more than cutting sodium alone.
Manganese
High intakeA cofactor for bone formation, collagen, and the antioxidant enzyme that protects mitochondria. Best sources: whole grains, nuts, oats (3.6mg), pineapple, and spices — cinnamon at 17.5mg and turmeric at 19.8mg are extraordinary per 100g, though you eat those by the pinch.
Low intakeRare from ordinary diets. Deficiency shows as poor bone development, impaired glucose tolerance and skin changes.
AffectsBones, connective tissue, antioxidant defence, glucose handling. One of the few nutrients where a plant-heavy diet has the clear advantage — plants carry nearly all of it, and animal foods have almost none.
Mercury
High intakeNot a nutrient — a contaminant, and the only column here with no safe upside. Methylmercury accumulates up the food chain, so long-lived predatory fish carry the most. It crosses the placenta and damages developing nerves.
Low intakeZero is ideal. Nothing is lost by avoiding it.
AffectsNervous system, kidneys, fetal brain development. Read it against omega-3, not alone: the fish highest in mercury here are tuna (35µg) and snapper (16µg), while sardines (1.3), clams (0.9) and shrimp (1) are near-zero and still rich in omega-3. Small, short-lived, low on the food chain is the rule. Pregnant women and young children should be strictest.
Monounsaturated fat (MUFA)
High intakeThe "olive oil effect" — lowers LDL while preserving HDL, supports vessel flexibility & insulin sensitivity. Best sources: olive oil, avocado, canola, nuts (almonds, peanuts).
Low intakeNo direct deficiency, but means you're getting more sat fat or refined carbs in its place — worse cholesterol profile.
AffectsHeart & arteries, cholesterol balance, metabolism.
Omega-3
High intakeLowers triglycerides & inflammation, modestly lowers BP, supports heart, brain, eyes & joints. Best sources: chia, oily fish (mackerel, salmon, sardines), flax, walnut.
Low intakeHigher cardiovascular & inflammatory risk, worsens omega-6 imbalance, may affect mood & skin. Common — most modern diets are short on it.
AffectsHeart & arteries, brain, eyes, joints, mood.
Omega-6
High intakeEssential, but excess (from refined seed oils & processed foods) shifts the omega-6:omega-3 ratio toward inflammation. Modern ratios ~15:1; ideal ≤4:1.
Low intakeRare — deficiency causes skin & growth issues. The goal isn't to eliminate, just to balance with more omega-3.
AffectsInflammation pathways, heart, skin, growth.
Phosphorus & oxalate
High intakeOnly a problem with reduced kidney function: phosphorus weakens bones & vessels; oxalate forms kidney stones.
Low intakeNo downside for blood pressure; not a concern with healthy kidneys.
AffectsKidneys, bones (tracked here only as a safeguard).
Potassium
High intakeRelaxes vessel walls and helps the body excrete sodium — lowers blood pressure (assuming healthy kidneys).
Low intakeRaises blood pressure, causes muscle weakness, cramps and irregular heartbeat.
AffectsHeart rhythm, blood vessels, muscles, nerves, kidneys.
Protein
High intakeExcess (esp. from processed/red meat) burdens kidneys over time and adds saturated fat & sodium.
Low intakeMuscle loss, poor wound healing, weakened immunity.
AffectsMuscles, kidneys, immune system.
Purines
High intakeBroken down into uric acid. Too much can trigger gout (crystals in joints) and kidney stones in susceptible people, and high uric acid is linked to higher blood pressure. Highest in organ meats (liver, kidney), oily/small fish (sardines, herring, tuna), and yeast-based bouillon cubes.
Low intakeNo downside — the body makes its own. Matters mainly if you have gout, hyperuricemia or stones; otherwise a minor concern. Coffee and dairy are mildly protective.
AffectsJoints (gout), kidneys (stones), blood pressure. Only a real lever for people prone to high uric acid.
Saturated fat
High intakeRaises LDL ("bad") cholesterol, stiffens and clogs arteries — palm, coconut, butter are highest.
Low intakeBetter cholesterol and more flexible arteries, especially when replaced with mono/polyunsaturated fats.
AffectsHeart & arteries, liver.
Selenium
High intakePowers the glutathione peroxidase enzymes — the body’s own antioxidant defence — and activates thyroid hormone. Best sources: brazil nuts (1917µg, extraordinary), seafood, offal, eggs, oats.
Low intakeWeaker antioxidant defence and immunity, impaired thyroid conversion; severe deficiency damages heart muscle. Plant levels depend entirely on soil selenium, which varies enormously by region.
AffectsAntioxidant defence, thyroid, immunity, fertility. The narrowest safe range of any mineral here: the target is ~55µg a day and toxicity starts near 400µg. One brazil nut is ~95µg — one or two daily is a supplement, a handful is too much.
Sodium
High intakePulls water into the bloodstream, raising blood volume and pressure; drives hypertension and fluid retention.
Low intakeLowers blood pressure; very low levels (rare from diet) can cause cramps, dizziness, low energy.
AffectsHeart & arteries, kidneys, brain (stroke risk).
Trans fat
High intakeUniquely bad — raises LDL and lowers HDL at the same time. No safe level; WHO recommends <1% of daily calories. Mostly from partially hydrogenated oils, fried packaged snacks, some margarines & creamers.
Low intakeThe clear goal — closer to zero, the better. Choose oils declaring 0g trans fat; avoid foods listing "partially hydrogenated" oil.
AffectsHeart & arteries (severely), inflammation, insulin sensitivity.
Vitamin A
High intakeVision (especially in low light), immune defence, skin, and cell growth. Comes two ways: retinol from animal foods, absorbed directly, and beta-carotene from orange and dark-green plants, which the body converts as needed. Best sources: cow liver (9442µg — extreme), red palm oil, carrot, ugu, spinach, tatashe.
Low intakeNight blindness first, then dry eyes and — untreated — permanent blindness. Still one of the leading causes of preventable childhood blindness worldwide. Also weakens immunity and skin repair.
AffectsEyes, immunity, skin, growth. Two cautions: it is fat-soluble, so greens need a little oil for it to be absorbed; and retinol from liver can reach toxic levels — a single 100g portion is several days’ worth, which is why liver is an occasional food and why pregnant women are told to limit it. Beta-carotene from plants carries no such risk.
Vitamin B1
High intakeThiamine — converts carbohydrate into usable energy, so the more carbohydrate a diet carries, the more it needs. Also required for nerve function. Best sources: pistachios, oats, groundnuts, whole grains, beans.
Low intakeFatigue, irritability, nerve pain and numbness; severe deficiency is beriberi. Two classic causes: polished white rice, since milling strips the thiamine-rich bran, and heavy alcohol use, which blocks absorption.
AffectsEnergy metabolism, nerves, heart. The loop that matters: a diet built on refined carbs raises the thiamine requirement while removing the main source. Beans, groundnuts and whole grains alongside close it.
Vitamin B6
High intakePyridoxine — runs amino acid metabolism, builds haemoglobin, and makes serotonin, dopamine and GABA, so it sits directly under mood and sleep. Also helps clear homocysteine alongside folate and B12. Best sources: pistachios (1.12mg), cow liver, salmon, chicken, banana, potato.
Low intakeAnaemia, cracked lips and sore tongue, weakened immunity, low mood, irritability and in severe cases confusion or seizures.
AffectsBlood, brain chemistry, immunity, homocysteine. Unusually for a water-soluble vitamin, very high supplemental doses cause nerve damage — food amounts never do, but B6 supplements above ~100mg a day are genuinely risky.
Vitamin B12
High intakeBuilds red blood cells, maintains the myelin sheath around nerves, and works with folate to clear homocysteine. It is made by bacteria, not by plants or animals — animals accumulate it, plants never do. So it is the one nutrient in this table with a hard dividing line: every animal food has some, and every plant food is a true zero, not a small number. Densest sources by far are offal (cow liver 70µg, kidney 27µg) and oily fish (Titus 19µg, herring 14µg, sardines 9µg).
Low intakeMegaloblastic anaemia and — more seriously — nerve damage that can become permanent: numbness, tingling, poor balance, memory and mood changes. Deficiency builds slowly because the liver stores years' worth, so symptoms often appear long after intake drops. Highest risk: strict vegetarians and vegans, older adults (absorption falls with age), and anyone on long-term metformin or acid-reducing drugs.
AffectsBlood, nerves, brain, DNA synthesis. Adults need ~2.4µg a day, so a single portion of fish or a little offal each week covers it comfortably. Anyone eating no animal food at all needs a supplement or fortified food — there is no plant workaround, and this is the one deficiency a plant-based diet cannot solve with better food choices.
Vitamin C
High intakeBuilds collagen — the scaffolding of skin, blood vessels, gums and healing wounds — and works as the body's main water-soluble antioxidant. It also multiplies iron absorption from plant sources several-fold, so citrus or peppers eaten alongside beans or greens pulls far more iron out of them. Best sources: guava (228mg, more than three oranges), peppers (ata rodo 144mg, tatashe 128mg), agbalumo, kiwi, pawpaw, citrus.
Low intakeSlow wound healing, bleeding gums, easy bruising, fatigue; severe deficiency is scurvy. Humans are among the few mammals that can't make their own, so it has to come from food daily — the body doesn't store it.
AffectsSkin & collagen, immune function, blood vessels, iron absorption. Heat and water destroy it — boiling loses the most, and long-simmered soups lose more than raw or briefly-cooked vegetables. The numbers here are for the food as listed, so a raw pepper delivers far more than the same pepper after an hour in a pot.
Vitamin D
High intakeControls calcium absorption — without it dietary calcium is largely wasted, so it underwrites everything the calcium column promises. Also supports immunity and muscle. Food sources are few: oily fish (herring 16µg, Titus 14µg, salmon 13µg), egg yolk, liver.
Low intakeWeak bones (rickets in children, osteomalacia in adults), muscle weakness, frequent infections, low mood. Widespread even in sunny countries — indoor work and covering up both cut what the skin makes.
AffectsBones, calcium absorption, immunity, muscle. Mostly not a food nutrient: skin makes it from sunlight, and 15–30 minutes of midday sun on arms and face does more than any meal in this table. Deeper skin tone needs longer exposure for the same result.
Vitamin E
High intakeThe main fat-soluble antioxidant — it protects cell membranes and circulating fats from oxidation, which matters because oxidised LDL is what damages artery walls. Overwhelmingly a plant-oil and seed nutrient: sunflower oil (41mg), groundnuts, hazelnuts, egusi, palm oil.
Low intakeRare from diet alone. Shortfall shows as nerve damage, muscle weakness and poor immune response; the real risk sits with fat-malabsorption conditions rather than ordinary eating.
AffectsCell membranes, arteries, nerves, immunity. Requirement rises with polyunsaturated fat intake — conveniently the oils highest in PUFA are also highest in vitamin E, so they arrive together.
Vitamin K1
High intakePhylloquinone — the plant form. Essential for blood clotting, and it activates the proteins that steer calcium into bone rather than into artery walls, so it works alongside calcium rather than competing with it. Overwhelmingly a leafy-green nutrient: spinach, ewedu, ugu, bitterleaf, cabbage, okra. Fat-soluble, so cooking greens in a little oil improves absorption.
Low intakeEasy bruising and slow clotting; long-term shortfall is linked to lower bone density and more arterial calcification.
AffectsBlood clotting, bones, arteries. One caution: anyone on warfarin should keep intake steady rather than high or low — the drug works by blocking vitamin K, so swings in leafy greens swing the dose. Newer anticoagulants aren't affected.
Zinc
High intakeRuns over 300 enzymes: immune response, wound healing, taste and smell, testosterone production, and DNA synthesis. Best sources: egusi (10mg), crab, red meat, gizzard, pumpkin seeds, cashews.
Low intakeFrequent infections, slow wound healing, hair loss, loss of taste, poor appetite, delayed growth in children. Common where diets lean on grains and legumes, because phytates bind zinc and cut absorption.
AffectsImmunity, healing, growth, fertility, taste. Animal zinc absorbs far better than plant zinc — soaking, sprouting and fermenting legumes and grains reduces phytates and helps.