No experimental data are available from which to calculate an AI for life stage groups other than adults as a whole.

The AI for choline in all forms for men in all age groups is 550 mg and for women is 425 mg. It is not known whether women have the same requirement on a body weight basis as men, but this AI is likely to be adequate on the basis of the earlier discussion on gender. Although there is some evidence that transport across the blood-brain barrier is diminished in the elderly, which suggests the possibility of a higher requirement than for younger adults (Cohen et al., 1995), no adjustment has been made in the AI for the elderly.

The need for choline is probably higher for pregnant than for nonpregnant women on the basis of animal data. Pregnancy renders female rats as vulnerable to deficiency as males (Zeisel et al., 1995). During pregnancy in humans (Welsch 1978; Welsch et al., 1981), guinea pigs (Swiery and Yudilevich, 1985; Swiery et al., 1986; Yudilevich and Sweiry, 1985), and rats (Jorswieck, 1974) large amounts of choline are delivered to the fetus through the placenta. Transport of choline from mother to fetus depletes maternal stores of choline; the choline concentration of maternal liver fell from a mean of 130 µmol/L in adult nonpregnant rats to 38 µmol/L in late pregnancy (Gwee and Sim, 1978).

Choline availability during embryogenesis and perinatal development may be especially important. In rats fed adequate diets during pregnancy, postnatally, and at weaning, 1 mmol/day of extra dietary choline results in long-lasting enhancement of spatial memory