Table 2

Evidence for major nutritional supplements.

Whey protein
The milk protein-supplemented group showed greater bone callus in area and volume than the control group in tibia fracture in mice (Yoneme et al., 2015).
In knee arthroplasty, the placebo group had large quadriceps muscle atrophy at -14.3 ± 3.6% change after two weeks from surgery compared to -3.4 ± 3.1% in the supplemented group. Positive effects were also evident at six weeks of follow-up (Dreyer et al., 2013).
In older adults with sarcopenia, a systematic review concluded that providing protein plus strength exercises was significantly more effective in preventing age-related muscle loss than the group using only strength exercises without protein supplementation (Liao et al., 2017).
In athletes after two weeks of inactivity, the creatine-supplemented group showed greater changes in the muscle cross-sectional area of the fibre (10% higher) and in maximal strength (25% higher) during the rehabilitation phase (Hespel et al., 2001).
In healthy people in the immobilisation phase, creatine was able to prevent the decrease of muscle GLUT4 during immobilisation, increasing its content by 9% during the rehabilitation period compared to a decrease of 20% in the control group (Eijnde et al., 2001).
Beta-hydroxy-methyl-butyrate (β-hmb)
In a systematic review conducted in older adults for prevention of sarcopenia, increased muscle mass was obtained in the HMB group (0.352 kg; 95% CI: .11, .594) without showing significant changes in muscle strength (Wu et al., 2015).
The use of β-hmb was more potent in reducing muscle catabolism (.38 ± .04) than leucine (.76 ± .04) and α-ketoisocaproate (.56 ± .04, p < .05) (Duan et al., 2018).
Systematic review in patients with arthritis, decreased pain and inflammation-related symptoms, with similar results to ibuprofen and diclofenac sodium (Daily et al., 2016).
The review showed the usefulness of curcumin in patients with osteoarthritis by inhibiting the gene expression of COX-2 but not COX-1, inhibiting the production of nitric oxide unlike the anti-inflammatory drugs (NSAIDs) studied. However, it was less effective than NSAIDs in blocking PGE2 (Henrotin et al., 2013).
Vitamin D
Vitamin D receptor (VDR) is expressed in the muscle stem cells that provide muscle regeneration after injury (Braga et al., 2017).
Systematic review published in 2015 showed conflicting results among the studies included in recovery of strength after inducing muscle damage due to exercise (Minshull et al., 2015).
Omega 3
Study with six weeks of supplementation with 3 grams per day did not alter strength, pain or inflammatory markers of muscle damage after 50 maximum repetitions of eccentric isokinetic knee extension exercises (Da Boit et al., 2017).
Study conducted on 22 paddlers, supplementation of 6 grams per day of fish oil (with 1.2 g DHA and 2.4 g EPA) for four weeks decreased the production of TNFα, IFN-γ and IL-1β while increasing IL-6 and IL-10 (Delfan et al., 2015).
Study conducted on young aerobic endurance athletes supplemented with 3.6 grams per day for six weeks did not alter levels of cytokines, creatine kinase or immune cell numbers (Da Boit et al., 2017).
Tart cherry extract
In vitro study showed that tart cherry extract can reduce COX-2 activity by 38.3%, which is equivalent to the effect of anti-inflammatory drugs such as ibuprofen or naproxen (Bell et al., 2013).
A study of 16 semi-professional soccer players using 30 ml of tart cherry extract twice daily showed that IL-6 levels decreased significantly compared to the control group after intense intermittent exercise (Bell, Stevenson et al., 2016).
In half-marathon runners, inflammatory markers were 47% lower in the tart cherry extract group compared to placebo (p = .053) (Levers et al., 2016).