How vitamin D helps exercise (IGF) – RCT Nov 2016

Vitamin D supplementation affects the IGF system in men after acute exercise.

Growth Horm IGF Res. 2016 Nov 5;30-31:45-51. doi: 10.1016/j.ghir.2016.11.002. [Epub ahead of print]
Darr RL1, Savage KJ2, Baker M3, Wilding GE4, Raswalsky A5, Rideout T6, Browne RW7, Horvath PJ8.

• 1Department of Kinesiology, Saginaw Valley State University, University Center, GN205 7400 Bay Rd. University Center, MI 48710, USA; Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA. rldarr at svsu.edu.
• 2Department of Biology, St. John Fisher College, ISHS 212 3690 East Avenue, Rochester, NY 14618, USA. ksavage at sjfc.edu.
• 3Department of Biostatistics, University at Buffalo, B1148 Center for Tomorrow, Amherst, Buffalo, NY 14260, USA. markbake at buffalo.edu.
• 4Department of Biostatistics, University at Buffalo, B1148 Center for Tomorrow, Amherst, Buffalo, NY 14260, USA. gwilding at buffalo.edu.
• 5Department of Exercise and Nutrition Sciences, University at Buffalo, 3435 Main St. Buffalo, NY 14214, USA. ajr24 at buffalo.edu.
• 6Department of Exercise and Nutrition Sciences, University at Buffalo, 3435 Main St. Buffalo, NY 14214, USA. rideout at buffalo.edu.
• 7Department of Biotechnical and Clinical Laboratory Sciences, University at Buffalo, 26 Cary Hall, Buffalo, NY 14214, rwbrowne at buffalo.edu.
• 8Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY, USA. phorvath at buffalo.edu.

OBJECTIVE:
Contradictory data between the Insulin-Like Growth Factor System (IGF) system and exercise may be due to alteration in IGF binding proteins.
Vitamin D (D) deficiency has been related to muscle weakness and Insulin Like Growth Factor Binding Protein 3 (IGFBP3). A Vit. D and acute exercise merge is proposed to modify the IGF system.

DESIGN:
D insufficient and deficient men (39.0±8.6yo with serum D (25OH D) 20.0±7.7ng/mL) did 1 hour of

• stretching (ST),
• aerobic (AB), and
• resistance (RT) exercises,

before and after 28d of 4000IU/d Vit. D3 (D, n=6) or Placebo (P, n=7).

• ST, a time/attention control visit, interchanged unreceptive movements.
• AB was moderate intensity treadmill walking.
• RT rotated moderate strength 50% 1-RM repetitions (15, 10) of squat, bench press, leg press, and lat pull down.

Serum Total IGF1 (TIGF1), Insulin Like Growth Factor Binding Protein 1 (IGFBP1), and IGFBP3 were measured before (T1, fasting), immediately after (T2), and 2h post (T3) exercise.

RESULTS:
After ST, IGFBP3 was greater in the D group at T2 (2948, 2130ng/mL; p<0.03) and T3 (3087, 2212; p<0.02). During RT, TIGF1 decreased in the Placebo (P) group from T1 to T3 (151.4, 107.3ng/mL; p<0.05), while IGFBP1 increased in the D group from T1 to T3 (26.5, 96.2ng/mL; p<0.05). RT IGFBP3 was greater at T1, T2, and T3 in the D group (2932.5, 2110.7; p<0.03), (3163.9, 2392.5; p<0.04), and (3355.3, 2353.1; p<0.01). In AB, IGFBP3 was greater in the D group at T2 (3128.6, 2226.3.0; p<0.04) and T3 (2949.7, 2135.1; p<0.05).

CONCLUSION:
D supplementation amplified IGFBP3 after low or moderate activity which may increase the delivery of IGF1 to tissues. Resistance exercise with D not only increased IGFBP3 and IGFBP1 levels but also conserved TIGF1 levels, possibly shifting the IGF system for enriched muscle well-being.

PMID: 27863277 DOI: 10.1016/j.ghir.2016.11.002 publisher wants $36 for the PDF