Intended for healthcare professionals

CCBYNC Open access

Rapid response to:

Research

Fruit and vegetable intake and incidence of type 2 diabetes mellitus: systematic review and meta-analysis

BMJ 2010; 341 doi: https://doi.org/10.1136/bmj.c4229 (Published 19 August 2010) Cite this as: BMJ 2010;341:c4229

Rapid Response:

Dietary Nitrate vs. Diabetes?

Sirs:
The new meta-analysis by Carter et al.(1) confirms previous
epidemiological evidence linking diets rich in green leafy vegetables - as
opposed to fruits and vegetables overall - to reduced risk for type 2
diabetes. Consideration should be given to the possibility that this
likely protection is mediated by the high nitrate content of green leafy
vegetables.(2) Recent research establishes that dietary nitrate can give
rise to plasma nitrite that in turn can be reduced to nitric oxide (NO),
independent of NO synthase activity.(3) In rodent skeletal muscle, NO has
been shown to activate AMPK, boost expression of GLUT4, and promote
mitochondrial biogenesis - all effects that should be conducive to good
insulin sensitivity.(4-6) Rodent and clinical studies should evaluate the
impact of dietary nitrate on insulin sensitivity and glycemic control.

Sincerely, Mark F. McCarty, markfmccarty@gmail.com

References

(1) Carter P, Gray LJ, Troughton J, Khunti K, Davies MJ. Fruit and
vegetable intake and incidence of type 2 diabetes mellitus: systematic
review and meta-analysis. BMJ 2010; 341:c4229.

(2) Hord NG, Tang Y, Bryan NS. Food sources of nitrates and
nitrites: the physiologic context for potential health benefits. Am J Clin
Nutr 2009; 90(1):1-10.

(3) Webb AJ, Patel N, Loukogeorgakis S, Okorie M, Aboud Z, Misra S
et al. Acute blood pressure lowering, vasoprotective, and antiplatelet
properties of dietary nitrate via bioconversion to nitrite. Hypertension
2008; 51(3):784-790.

(4) Lira VA, Soltow QA, Long JH, Betters JL, Sellman JE, Criswell
DS. Nitric oxide increases GLUT4 expression and regulates AMPK signaling
in skeletal muscle. Am J Physiol Endocrinol Metab 2007; 293(4):E1062-
E1068.

(5) Nisoli E, Falcone S, Tonello C, Cozzi V, Palomba L, Fiorani M et
al. Mitochondrial biogenesis by NO yields functionally active mitochondria
in mammals. Proc Natl Acad Sci U S A 2004; 101(47):16507-16512.

(6) Wadley GD, McConell GK. Effect of nitric oxide synthase
inhibition on mitochondrial biogenesis in rat skeletal muscle. J Appl
Physiol 2007; 102(1):314-320.

Competing interests:
None declared

Competing interests: No competing interests

24 August 2010
Mark F. McCarty
President, NutriGuard Research
1051 Hermes Ave., Encinitas, CA 92024