* Magnesium deficiency is common among women with PMS (Am J Clin Nutr, 1981; 34: 2364-6; Ann Clin Biochem, 1986; 23: 667-70). Ideally, take 400 mg/day but, in one trial, just 200 mg/day for two months significantly reduced fluid retention, weight gain, oedema, breast tenderness and abdominal bloating (J Women’s Health, 1998; 7: 1157-65).

* Vitamin B6 (50-400 mg daily) can relieve symptoms of PMS (Br J Obstet Gynaecol, 1990; 97: 847-52; BMJ, 1999; 318: 1375-81) if taken for several months. Some women, however, may experience gastrointestinal problems with doses above 200 mg per day.

* Women who consume more dietary calcium are less likely to suffer severe PMS (Am J Obstet Gynecol, 1993; 168: 1640). Supplements can also help (Am J Obstet Gynecol, 1993; 168: 1417-23) - 1200 mg/day can reduce PMS symptoms by 48 per cent (Am J Obstet Gynecol, 1998; 179: 444-52).

* Potassium is similarly helpful. Taking 600 mg of potassium gluconate daily can relieve symptoms of bloating, fatigue and irritability (J Orthomolec Med, 1998; 13: 215-22). The full effect of potassium takes around four cycles to produce results.