Inhibitory effect of nuts on iron absorption

Am J Clin Nutr. 1988 Feb;47(2):270-4. doi: 10.1093/ajcn/47.2.270.


The effects on iron absorption of nuts, an important source of dietary protein in many developing countries, were measured in 137 Indian women. When the absorption from bread and nut meals (walnuts, almonds, peanuts, and hazelnuts) was compared with that from bread meals, the overall geometric mean absorption from the nut meals (1.8%) was significantly less than from the bread meals alone (6.6%, t = 9.8, p less than 0.0005). In contrast, coconut did not reduce absorption significantly. All the nuts tested contained significant amounts of two known inhibitors of Fe absorption (phytates and polyphenols) but the amounts in coconut were significantly less than in the other nuts. Fifty milligrams ascorbic acid overcame the inhibitory effects of two nuts that were tested (Brazil nuts and peanuts). This is different from that found previously for soy protein, another potent inhibitor of Fe absorption.

Publication types

  • Clinical Trial
  • Comparative Study
  • Controlled Clinical Trial

MeSH terms

  • Absorption
  • Ascorbic Acid / administration & dosage
  • Ascorbic Acid / blood
  • Bread
  • Cocos
  • Dietary Proteins / metabolism*
  • Female
  • Humans
  • India / ethnology
  • Iron / antagonists & inhibitors
  • Iron / blood*
  • Nuts*
  • Socioeconomic Factors
  • South Africa
  • Urban Population


  • Dietary Proteins
  • Iron
  • Ascorbic Acid