Which nutrients relate to the immune system?

Immunity is a word used very broadly in advertising, but what Thai regulation recognises has a clear boundary, and it covers eight nutrients.

Which eight?

Under the annex to Thai Ministry of Public Health Notification No. 447 (B.E. 2566), the statement "contributes to the normal function of the immune system" is available for:

• Vitamin C
• Vitamin D
• Vitamin A
• Zinc
• Iron
• Folate
• Vitamin B6
• Vitamin B12

What does the statement mean?

It means these nutrients take part in the processes by which the immune system works normally.

That is why the wording is about normal function rather than about raising it beyond normal.

Where do they come from in food?

Vitamin C: Indian gooseberry, guava, orange, papaya, sweet pepper, broccoli.

Vitamin D: oily fish, egg yolk, and what the body makes when skin is exposed to sunlight.

Vitamin A: liver, egg yolk, milk, pumpkin, carrot, sweet potato and dark leafy greens.

Zinc: oysters, red meat, poultry, seafood, dried beans, pumpkin seeds.

Iron: pork blood, liver, red meat, dark leafy greens, dried beans.

Folate: dark leafy greens, dried beans, liver, citrus fruit.

Vitamin B6: fish, meat, potato, banana, wholegrains.

Vitamin B12: meat, fish, shellfish, eggs, milk.

How do you know whether you are getting enough?

The most direct check is whether a week's eating covers these groups: leafy vegetables, fruit, protein from animals or beans, and wholegrains.

If you supplement, what should you look at?

Which of the eight the formulation contains and at what amount against the reference intake, and the upper intake levels — zinc, iron and vitamin A in particular have ceilings.

Dietary supplements are not intended to prevent, treat or cure any disease.