Effect of Altering Dietary n-6:n-3 Polyunsaturated Fatty Acid Ratio with Plant and Marine-Based Supplement on Biomarkers of Bone Turnover in Healthy Adults

Nutrients. 2017 Oct 24;9(10):1162. doi: 10.3390/nu9101162.


Although there is accumulating evidence for a protective role of n-3 polyunsaturated fatty acids (n-3 PUFAs) on bone health, there are limited studies that examine the effect of altering dietary n-6:n-3 PUFA ratio with plant and marine sources of n-3 PUFA on bone health. Healthy adults (n = 24) were randomized into an eight-week crossover study with a four-week washout between treatments, with each subject consuming three of four diets. The four diets differed in the dietary n-6:n-3 PUFA ratios and either had an algal oil supplement added or not: (Control diet (10:1); α-linolenic acid (ALA) diet (2:1); Eicosapentaenoic acid/Docosahexaenoic acid (EPA/DHA) diet (10:1 plus supplement (S) containing EPA/DHA; Combination diet (2:1 + S)). The supplement was microalgae oil that provided 1 g EPA + DHA/day. Flaxseed oil and walnuts provided 8.6 g of ALA/day in the 2:1 diets. Serum levels of c-telopeptide (CTX), procollagen Type I N-terminal peptide, and osteocalcin showed significant correlation with age but none of the bone markers or peroxisomal proliferator-activated receptor-γ mRNA expression was significantly different between the diets. Serum CTX was negatively associated with red blood cell membrane linoleic acid and ALA and positively associated with membrane DHA. Neither altering dietary n-6:n-3 PUFA ratio from a 10:1 to a 2:1 ratio nor adding EPA/DHA supplement significantly changed bone turnover in the short term in healthy adults.

Keywords: ALA; EPA/DHA; bone turnover; dietary n-3 fatty acids; peroxisomal proliferator activated receptor γ.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Biomarkers
  • Bone Remodeling / drug effects*
  • Collagen Type I / blood
  • Cross-Over Studies
  • Diet*
  • Dietary Supplements
  • Fatty Acids, Omega-3 / administration & dosage*
  • Fatty Acids, Omega-6 / administration & dosage*
  • Female
  • Fish Oils / administration & dosage
  • Humans
  • Insulin-Like Growth Factor I / genetics
  • Insulin-Like Growth Factor I / metabolism
  • Male
  • Middle Aged
  • Nutrition Assessment
  • Osteocalcin / blood
  • PPAR gamma / blood
  • PPAR gamma / genetics
  • Patient Compliance
  • Peptide Fragments / blood
  • Peptides / blood
  • Plant Oils / administration & dosage
  • Procollagen / blood
  • RNA, Messenger / blood
  • RNA, Messenger / genetics
  • Single-Blind Method


  • Biomarkers
  • Collagen Type I
  • Fatty Acids, Omega-3
  • Fatty Acids, Omega-6
  • Fish Oils
  • IGF1 protein, human
  • PPAR gamma
  • Peptide Fragments
  • Peptides
  • Plant Oils
  • Procollagen
  • RNA, Messenger
  • collagen type I trimeric cross-linked peptide
  • procollagen Type I N-terminal peptide
  • Osteocalcin
  • Insulin-Like Growth Factor I