How do recommended intakes change with age?

Reference intake tables tend to get read as a single number, when in fact they are set separately by sex and life stage.

What rises with age?

Calcium. The US reference intake, as published by the Office of Dietary Supplements, is 1,000 mg a day for adults, rising to 1,200 mg for women over 50 and for everyone over 70.

Vitamin D. 15 micrograms, or 600 IU, a day for adults, rising to 20 micrograms or 800 IU for people over 70.

What falls?

Iron, for women. The recommended intake is 18 mg a day between 19 and 50, and 8 mg from age 51, the same as for adult men.

This is the part most often missed: the figure for women goes down, not up, at the next age band.

What stays the same but depends on absorption?

Vitamin B12. The recommended intake for adults is 2.4 micrograms a day and does not change with age, but absorption relies on a specific process in the stomach, so the amount eaten and the amount taken up are not always the same figure.

What about protein?

General international guidance sits at around 0.8 g per kilogram of body weight a day for adults. Under the annex to Thai Ministry of Public Health Notification No. 447 (B.E. 2566), protein contributes to growth and maintenance of muscle mass.

How should these figures be used?

They are population reference values, not personal targets. Use them as a starting point for seeing how far a usual diet sits from them.

Product labels in Thailand show a percentage against the Thai Recommended Daily Intakes, which is a different set of figures from the US values cited above.

When should you revisit?

When you move into a different age band, when your eating pattern changes, and when you start regular medication — in the last case, speak to a doctor or pharmacist.

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