Stress Hormones and Diet: Cortisol

Cortisol is probably the most well known of the hormones associated with stress. It’s been said that when cortisol is elevated you are by definition experiencing stress. Like all hormones, it can be good or bad depending on the context. Without getting into that context let’s look at how what you eat affects cortisol:

1. There is evidence that a very high protein diets increases cortisol (1,2,3,4,5).

2. In some studies, high protein meals appear to increase cortisol relative to carbohydrates and fats (6,7). In other studies, carbohydrates appear to increase cortisol relative to protein and fats (15). These inconsistent findings may be a result of a number of variable factors, including specific amino acids in the tested protein (6), an individual’s glucose tolerance (16), body fat quantity (17), and body fat type (18).

2. During exercise, carbohydrates reduce cortisol levels (8,9,10,11,12,13,22), although conflicting studies exist (14). Fructose appears to produce less of a reduction in cortisol levels during exercise than glucose and sucrose (19,20,21).

3. Sugar in the form of glucose may increase cortisol after mental stress (23,24).

4. Caffeine and coffee increase cortisol in response to mental stress (25,26), exercise (27,28), and resting conditions (29,30,31). This effect varies, but largely remains regardless of caffeine tolerance (32,33), gender (34), or whether the caffeine is consumed in coffee (35).

5. Black tea appears to decrease cortisol in response to psychological stress (36) and exercise (37), but not during resting conditions (38).

6. Fish oil has been shown to lower cortisol from psychological stress (39,40), exercise (41), and in resting conditions (42,43).

7. Vitamin C has reduced cortisol during intense exercise in some studies (44,45), but not in others (46,47,48).

8. Magnesium has been shown to lower the cortisol response to intense exercise in some studies (49,50) and raise it in others (51).

References:

1. http://www.sciencedirect.com/science/article/pii/0024320587900865
2. http://www.sciencedirect.com/science/article/pii/002604958190055X
3. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3033415/
4. http://www.ncbi.nlm.nih.gov/pubmed/16423633
5. http://jama.jamanetwork.com/article.aspx?articleid=1199154
6. http://jcem.endojournals.org/content/57/6/1111.short
7. http://www.psychosomaticmedicine.org/content/61/2/214.short
8. http://www.ncbi.nlm.nih.gov/pubmed/20169359
9. http://www.ncbi.nlm.nih.gov/pubmed/16320174
10. http://www.ncbi.nlm.nih.gov/pubmed/20091182
11. http://www.ncbi.nlm.nih.gov/pubmed/525365
12. http://www.ncbi.nlm.nih.gov/pubmed/9877150
13. http://www.ncbi.nlm.nih.gov/pubmed/10408318
14. http://www.jappl.org/content/82/5/1662.full
15. http://www.sciencedirect.com/science/article/pii/S0031938410003239
16. http://jcem.endojournals.org/content/86/3/1149.full
17. http://jcem.endojournals.org/content/87/8/3984.short
18. http://jcem.endojournals.org/content/96/9/2882.abstract
19. http://ukpmc.ac.uk/abstract/MED/2733576
20. http://jap.physiology.org/content/51/4/783.abstract
21. http://jap.physiology.org/content/61/3/1180.short
22. http://etd.library.pitt.edu/ETD/available/etd-11042010-211642
23. http://www.sciencedirect.com/science/article/pii/S0018506X02917666
24. http://jcem.endojournals.org/content/82/4/1101.full.pdf
25. http://www.ncbi.nlm.nih.gov/pubmed/10826397
26. http://www.ncbi.nlm.nih.gov/pubmed/8084974
27. http://www.ncbi.nlm.nih.gov/pubmed/2321541
28. http://www.ncbi.nlm.nih.gov/pubmed/10852448
29. http://www.ncbi.nlm.nih.gov/pubmed/8951977
30. http://jn.nutrition.org/content/141/4/703.full
31. http://www.ncbi.nlm.nih.gov/pubmed/17998023
32. http://www.ncbi.nlm.nih.gov/pubmed/16204431
33. http://www.ncbi.nlm.nih.gov/pubmed/2195579
34. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2249754/?tool=pmcentrez
35. http://jn.nutrition.org/content/141/4/703.full
36. http://www.springerlink.com/content/m226111566k24u65/
37. http://www.jissn.com/content/7/1/11
38. http://www.springerlink.com/content/un63kmlau7wenux4/
39. http://www.ncbi.nlm.nih.gov/pubmed/12909818
40. http://www.sciencedirect.com/science/article/pii/S1262363607700393
41. http://www.sciencedirect.com/science/article/pii/S0952327807001093
42. http://www.ajcn.org/content/54/4/684.long
43. http://www.biomedcentral.com/content/pdf/1550-2783-7-31.pdf
44. http://jap.physiology.org/content/92/5/1970.full
45. http://www.ncbi.nlm.nih.gov/pubmed/11590482
46. http://ukpmc.ac.uk/abstract/MED/9286741
47. http://www.ncbi.nlm.nih.gov/pubmed/11258644
48. http://www.springerlink.com/content/hlykjma37w34pl78/
49. http://www.ncbi.nlm.nih.gov/pubmed/9794094
50. http://www.ncbi.nlm.nih.gov/pubmed/6527092
51. http://www.springerlink.com/content/c13762u7x0m3h147/

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