In a randomized, double-blind, multicenter trial of 59 HIV positive subjects, researchers studied the effect of high protein whey supplementation when compared to a matched isocaloric control supplement without added protein for patients with a history of weight loss (a typical and potentially dangerous factor for HIV positive patients).7 Following the 12-week study, researchers concluded that there was no observed difference in regard to increased energy intake or changes in weight/lean body mass.7 However, researchers stated that CD4 lymphocytes (white blood cells responsible for fighting bacteria, viruses and germs) did increase in the protein group, a potential benefit according to the authors.7 However, researchers also stated that gastrointestinal symptoms were more commonly reported in the high protein whey group.7 It is important to note that this study was supported by the whey supplement company, drawing into question the validity of accurate findings.7
A 1999 three-arm randomized controlled trial of 536 HIV patients with CD4 counts below 200 looked at the impact of nutrients on the prevention of weight loss over a four-month period.8 Researchers studied the implementation of three nutritional regimens to determine their effect on the prevention of weight loss in patients.8 Therapies consisted of a 500 kcal daily of caloric supplement with peptides and medium-chain triglycerides plus a multivitamin and mineral supplement, 500 kcal of a caloric supplement with whole protein and long-chain triglycerides plus a multivitamin and mineral supplement, and a multivitamin and mineral supplement only.8 At the conclusion of the four-month study, researchers concluded that no differences were observed (including the increased protein group), stating that caloric supplements did not provide a viable treatment modality for this population.8
In a 2003 study of 467 weight-stable HIV-infected men with CD4 counts lower than 200 were observed in regard to protein intake and body composition variables, including body cell mass (the depletion of which is a predictor of disease progression and death).9 Researchers concluded that increased protein intake was related to increased body cell mass, suggesting efficacy in the use of protein to boost health variables in HIV patients.9
Researchers in a 2006 study of children suffering from rapidly-progressing AIDS, examined the effect of a whey protein supplement in regard to erythrocyte glutathione concentration, T lymphocyte counts and occurrence of additional infections.10 In the prospective double-blind clinical trial, 18 HIV-infected children undergoing antiretroviral therapy were followed for four months.10 The subjects were divided into three groups and given whey protein, maltodextrin or placebo, followed by an evaluation of erythrocyte glutathione concentration, T lymphocyte counts and occurrence of additional infections.10 Results demonstrated that in the whey protein group, erythrocyte glutathione levels increased and co-infection occurrence decreased, while T lymphocytes remained unchanged when compared to the control group (placebo).10 Researchers concluded that the inclusion of a whey protein supplement was advisable for this population.10
Summary of Findings and Limitations
Though this brief review may appear to point to the overall benefits of increased protein intake and health-compromised people groups, it is important to note the existence of study limitations. Several of the studies reviewed involved very small sample sizes. Though this fact does not necessarily fully discount the findings, it does give reason to be cautious when evaluating the efficacy of information. Many of the studies reviewed also examined multiple factors combined with increased protein intake, making the definitive factor of efficacy more difficult to deduce. Further, as mentioned previously, one of the studies presented was funded by the maker of the protein supplement used in the study, thus giving reason to again be mindful of the bias potential. Length of the studies is also a factor to consider due to the fact that the relevance of data was not studied extensively in terms of long-term outcomes. Oftentimes interventions appear positive in the short-term but neutral or negative in the long-term. Further, though some benefit was shown in some of the presented studies, it is important to note that reduction in wound size or increased levels of CD4 levels for example, does not necessarily imply positive health outcomes for the individual overall. Symptom management, symptom reduction and more acceptable biomarkers do not always suggest optimal health, a point of key importance when evaluating treatment modalities.
It is always important to examine the level of risk associated with any type of intervention, even if the added measure appears to be harmless. Though protein is a necessary nutrient, an increase of consumption does not come without risk. Consuming large amounts of protein carries with it a significant amount of risk such as increased risk of cancer, diabetes and overall mortality.11 Eating a high protein diet also creates excessive strain on the kidneys, causing complications such as the formation of kidney stones and other kidney-related health issues.13 In addition, the inclusion of high protein supplements made from dairy products carries with it a considerable amount of risk due to the detrimental effects of dairy consumption. Higher mortality rates, cancer, fracture risk and heart disease can all be linked to the consumption of dairy, a fact that should give significant pause to the recommendation to increase the consumption of it, particularly in immune-compromised populations.,14, 15, 16
Conclusions and Future Research Opportunities
As reviewed above, some evidence appears to exist in regard to increased protein intake. However, study limitations exist and multiple risks exist to the implementation of increased protein intake. Additional research into alternative methods of improvement that do not involve increased protein intake would be wise to conduct, in addition to a more extensive evaluation of the risk-benefit ratio of protein intervention and the detrimental effects of engaging in such measures.
7. Sattler FR, Rajicic N, Mulligan K, et al. Evaluation of high-protein supplementation in weight-stable HIV-positive subjects with a history of weight loss: a randomized, double-blind, multicenter trial. American Journal of Clinical Nutrition. 2008;88(5):1313–1321. doi:10.3945/ajcn.2006.23583
8. Gibert CL, Wheeler DA, Collins G, et al. Terry Beirn Community Programs for Clinical Research on AIDS: randomized, controlled trial of caloric supplements in HIV infection. Journal of Acquired Immune Deficiency Syndrome. 1999;22:253–259.
9. Williams SB, Bartsch G, Muurahainen N, et al. Protein intake is positively associated with body cell mass in weight-stable HIV-infected men. Journal of Nutrition. 2003; 133(4): 1143-1146.
10. Moreno YF, Sgarbieri VC, da Silva MN, Toro AADC, Vilela MMS. Features of whey protein concentrate supplementation in children with rapidly progressive HIV infection. Journal of Tropical Pediatrics. 2006; 52(1): 34–38.
11. Levine ME, Suarez JA, Brandhorst S, et al. Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population. Cell Metabolism. 2014;19(3):407–417.
12. Fontana L, Klein S, O Holloszy J, Long-term low-protein, low-calorie diet and endurance exercise modulate metabolic factors associated with cancer risk. American Journal of Clinical Nutrition. 2006; 84(6):1456–1462.
13. Robertson W, Heyburn P, Peacock M, Hanes F, Swaminathan R. The effect of high animal protein intake on the risk of calcium stone-formation in the urinary tract. Clinical Science. 1979; 57(3):285-288.
14. Michaëlsson K, Wolk A, Langenskiöld S, et al. Milk intake and risk of mortality and fractures in women and men: cohort studies. British Medical Journal. 2014; 349 :6015.
15. Aune D, Rosenblatt DAN, Chan DSM, et al. Dairy products, calcium, and prostate cancer risk: a systematic review and meta-analysis of cohort studies. American Journal of Clinical Nutrition. 2015;101:87-117.
16. Chen M, Li Y, Sun Q, et al. Dairy fat and risk of cardiovascular disease in 3 cohorts of US adults. American Journal of Clinical Nutrition. 2016;104(5):1209–1217.