Essential nutrients: daily intake and deficiency signs

Night blindness, dry eyes (xerophthalmia), dry skin, frequent infections

Sources: Liver, eggs, dairy, carrots, sweet potato, spinach

Bone pain, muscle weakness, osteomalacia (rickets in children), low mood; very common in Swiss winters

Sources: Sunlight on skin, oily fish, egg yolk, fortified foods

Rare: nerve damage, poor coordination, muscle weakness, weakened immunity

Sources: Nuts, seeds, vegetable oils, avocado

Easy bruising, prolonged bleeding, weaker bones

Sources: Leafy greens, broccoli, fermented foods

Fatigue, irritability, nerve damage (beriberi); confusion and memory loss (Wernicke-Korsakoff) with heavy alcohol use

Sources: Whole grains, pork, legumes, seeds

Cracks at mouth corners, sore red tongue, sore throat, skin rash

Sources: Dairy, eggs, meat, almonds, mushrooms

Pellagra: dermatitis, diarrhoea, confusion

Sources: Poultry, fish, peanuts, whole grains

Rare: fatigue, numbness and burning in feet

Sources: Almost all foods; meat, avocado, mushrooms

Anaemia, depression, confusion, cracked lips, weakened immunity

Sources: Poultry, fish, potatoes, chickpeas, bananas

Rare: hair thinning, scaly red rash, brittle nails

Sources: Eggs, nuts, seeds, salmon

Megaloblastic anaemia, fatigue, mouth sores; neural-tube defects in pregnancy

Sources: Leafy greens, legumes, citrus, fortified grains

Fatigue, anaemia, tingling hands and feet, memory problems; essential to supplement on a vegan diet

Sources: Meat, fish, eggs, dairy, fortified foods

Scurvy: bleeding gums, easy bruising, slow wound healing, joint pain, fatigue

Sources: Citrus, peppers, kiwi, berries, broccoli

Fatty liver, muscle damage

Sources: Eggs, liver, meat, fish, soybeans

Long-term: low bone density, osteoporosis; acute: muscle cramps, tingling

Sources: Dairy, fortified plant milk, tofu, kale, almonds

Rare: weakness, bone pain, poor appetite

Sources: Meat, dairy, fish, nuts, grains

Muscle cramps and twitches, fatigue, irregular heartbeat, low calcium and potassium

Sources: Nuts, seeds, whole grains, dark chocolate, leafy greens

Rare from diet: headache, nausea, confusion (usually from overhydration or heavy sweating)

Sources: Salt, processed foods

Muscle weakness, cramps, constipation, irregular heartbeat

Sources: Potatoes, beans, bananas, leafy greens, yoghurt

Rare: occurs with sodium loss

Sources: Table salt

Fatigue, pale skin, shortness of breath, cold hands, brittle nails; the most common deficiency worldwide

Sources: Red meat, legumes, tofu, spinach; pair plant iron with vitamin C

Slow wound healing, hair loss, loss of taste and smell, frequent infections

Sources: Oysters, meat, seeds, legumes

Goitre, hypothyroidism: fatigue, weight gain, feeling cold

Sources: Iodised salt, fish, dairy, seaweed

Rare: weakened immunity, thyroid problems, heart muscle disease

Sources: Brazil nuts, fish, eggs, meat

Anaemia, low white cell count, nerve problems, weak bones

Sources: Shellfish, nuts, seeds, organ meat, cocoa

Rare: poor bone growth, skin rash

Sources: Whole grains, nuts, tea, legumes

Rare: impaired glucose tolerance

Sources: Broccoli, whole grains, meat

Very rare

Sources: Legumes, grains, nuts

Higher risk of tooth decay

Sources: Fluoridated water or salt, tea, fish

From depletion studies: possibly weaker bones, altered calcium and vitamin D metabolism, poorer concentration

Sources: Fruit, avocado, nuts, legumes, wine, coffee

In animals: weaker bones and connective tissue; human evidence limited

Sources: Whole grains, oats, beer, green beans, bananas, mineral water

In animals: impaired growth and iron absorption; not seen in humans. Nickel allergy is far more relevant

Sources: Cocoa, nuts, legumes, oats

In animals: possible effects on growth and glucose handling; no human deficiency known

Sources: Mushrooms, shellfish, black pepper, parsley, grains

Rare: anaemia, skin problems (eczema reported); precursor of histamine

Sources: Meat, fish, dairy, soy, grains

Muscle wasting, fatigue, tremors, poor blood sugar control

Sources: Eggs, meat, fish, dairy, lentils

Muscle loss, slow recovery; main trigger of muscle protein synthesis

Sources: Dairy, whey, meat, soy, beans

Fatigue, anaemia, poor collagen formation, slow growth; most likely limiting amino acid in grain-heavy diets

Sources: Meat, fish, eggs, legumes, quinoa

Fatty liver, poor growth, weaker antioxidant defence; often limiting in legume-heavy diets

Sources: Eggs, fish, meat, Brazil nuts, sesame

Confusion, low mood, fatigue; precursor of dopamine and adrenaline. Must be restricted in phenylketonuria (PKU)

Sources: Meat, fish, dairy, soy, nuts

Rare: fatty liver, weaker gut lining and immunity

Sources: Meat, cottage cheese, lentils, sesame

Low mood, poor sleep; precursor of serotonin, melatonin and niacin (pellagra risk)

Sources: Turkey, eggs, cheese, oats, seeds

Muscle loss, poor coordination, insomnia

Sources: Dairy, meat, soy, peanuts, mushrooms

Shortfall in illness or injury: slow wound healing, impaired immunity; precursor of nitric oxide

Sources: Meat, nuts, seeds, legumes

Lower glutathione (main antioxidant); contributes to the methionine target above

Sources: Eggs, poultry, garlic, onions, oats

Shortfall in severe illness, burns, trauma: gut lining and immune cell problems

Sources: Meat, eggs, dairy, tofu, cabbage

Body production may fall short of collagen needs; linked to poorer sleep and connective tissue

Sources: Gelatin, bone broth, meat, skin

Shortfall after injury or burns: slow wound healing

Sources: Gelatin, bone broth, dairy, eggs

Essential in PKU; low levels linked to low mood and thyroid hormone shortfall

Sources: Dairy, meat, fish, soy, almonds

Not a dietary concern; carries nitrogen from muscle to liver

Sources: Meat, fish, eggs, dairy

Not a dietary concern; rare genetic synthesis defect affects brain development

Sources: Asparagus, dairy, meat, potatoes

Not a dietary concern; used in the urea cycle and nucleotide synthesis

Sources: Meat, legumes, avocado, asparagus

Not a dietary concern; main excitatory neurotransmitter and source of umami flavour

Sources: Cheese, tomatoes, meat, soy sauce

Not a dietary concern; rare genetic synthesis defects cause seizures

Sources: Soy, eggs, dairy, meat, nuts

No direct requirement; depends on selenium intake (see Selenium)

Sources: Built in the body; needs selenium

Low intake is tolerated (ketosis), but very low intake can cause fatigue, headache, poor concentration, bad breath and constipation

Sources: Whole grains, potatoes, legumes, fruit, vegetables; limit added sugar to under 10% of energy

Muscle loss, oedema, weakened immunity, hair thinning, slow healing

Sources: Meat, fish, eggs, dairy, legumes, tofu

Dry flaky skin, dry eyes; linked to poorer heart and brain health

Sources: Oily fish, flax, chia, walnuts, algae oil

Rare: scaly skin, poor wound healing

Sources: Vegetable oils, nuts, seeds

Constipation; linked to higher risk of heart disease and colon cancer

Sources: Whole grains, legumes, vegetables, fruit

Thirst, dark urine, headache, dizziness, poor concentration

Sources: Drinks, fruit, vegetables, soups

Lower muscle creatine stores in vegetarians and vegans; possibly lower strength output and short-term memory

Sources: Meat, fish; supplement for plant-based diets

Primary deficiency is genetic: muscle weakness, low blood sugar, heart problems; dialysis can lower levels

Sources: Red meat, dairy

Production falls with age and statin use; linked to fatigue and muscle aches on statins

Sources: Organ meat, oily fish, meat, peanuts

Low levels linked to poorer eye, heart and bile function; essential for cats, not humans

Sources: Fish, shellfish, meat, poultry

Low levels linked to insulin resistance; studied in PCOS

Sources: Fruit, beans, grains, nuts

Low intake linked to higher risk of age-related macular degeneration and cataracts

Sources: Kale, spinach, egg yolk, corn, peppers

Low intake linked to higher heart disease risk and blood pressure

Sources: Berries, tea, coffee, cocoa, olive oil, red onions

Less diverse gut bacteria; constipation

Sources: Onions, garlic, leeks, chicory, cooled potatoes, oats

No deficiency as such; useful after antibiotics and for some gut conditions

Sources: Yoghurt, kefir, sauerkraut, kimchi, miso