Table 1.
Non-traditional protein sources: Summary of health effects from human, animal, and in vitro studies.
| Protein Source |
Human Studies (#) |
PDCAAS * (In Vitro) |
Potential Health Effects | Knowledge Gaps and Future Directions |
|---|---|---|---|---|
| Algae | 0 | 0.29–0.64 [121] |
Improved glycaemic status Appetite control Improved liver function in NAFLD Modulate antioxidant, anti-inflammatory and ACE inhibition actions for disease prevention |
Human clinical and protein bioavailability data needed Optimised algal growth conditions Protein extraction protocols Safety & toxicity testing Testing and selection of optimal species for human consumption |
| Cereal, Barley | 1 | 0.59–0.76 [122,123] |
Comparable with casein with respect LDL cholesterol, inflammation (CRP), oxidative stress and blood pressure | More human clinical data needed to determine whether effects are specific to barley as a whole food or protein fraction. |
| Cereal, Buckwheat | 1 | 0.041–0.5 [123] |
Lipid profile and inflammatory markers improved in a cohort with mild/moderate hypercholesterolemia |
More human clinical data needed to determine whether effects are specific to whole food or protein fraction. |
| Cereal, Oat |
1 | 0.67 [124] |
Hunger/appetite suppression Increased plasma insulin |
More human clinical data needed to determine whether effects are specific to whole food or protein fraction. |
| Cereal, Rice | 7 | 0.51–0.62 [124] |
Reduced pro-inflammatory cytokines. Compares well with whey for body composition with exercise |
Further analysis needed for different processing methods and |
| Cereal, Rye |
1 | 0.59 [122] |
Improved satiety Improved biomarkers of glycaemic control |
More human clinical data needed |
| Cereal, Wheat | 7 | 0.42–0.54 [123,125] |
Increased glycogen synthesis Supported exercise and muscle performance and reduced exercise-induced inflammation Myofibrillar protein synthesis lower than whey or casein Improve blood lipid profile and anti-hypertensive effects Assist with energy balance and improve satiety Elicits insulin response |
More human clinical data needed including myofibrillar synthesis and satiety Greater clarity whether effects are due to protein alone, or whole food |
| Fresh fruit | 0 | n/a | No studies identified |
|
| Fresh vegetable, potato |
4 | 0.87–1.0 [123] | Potato protein augments effect of myofibrillar protein synthesis Increased glucose control |
More human clinical data needed |
| Insect, Cricket (ground) Gryllus assimilis |
1 | 0.65–0.73 [126,127] |
Improved gut microbiome Reduced inflammation Reduced LDL cholesterol Bioactives (antioxidants, anti-inflammatories, ACE inhibition, DPP-IV inhibition) |
Human clinical data needed Scalability and consistency of production Production cost Overcoming the ‘yuck’ factor |
| Insect, Mealworm (ground) Tenebrio molitor |
1 | 0.54 [126] |
Slower, sustained amino acid digestion Improved glucose tolerance Improved lipid metabolism Potential anti-obesity effects Reduced homocysteine Bioactives (antioxidants, anti-inflammatories, ACE inhibition, DPP-IV inhibition) |
Human clinical data needed Scalability and consistency of production Production cost Overcoming the ‘yuck’ factor |
| Silkworm Bombyx mori |
0 | N/A for B. mori (Samia ricinii 0.86 [128]) |
Improved lipid metabolism Improved fatty liver disease Anti-inflammatory factors |
Human clinical data needed Scalability and consistency of production |
| Termites Macrotermes nigeriensis |
2 | 0.42 [127] |
Rich in protein Rich in minerals (Mg, Ca, K, P) Well tolerated and accepted for infant food supplementation |
Human clinical data needed Scalability and consistency of production |
| Snails | 0 | N/A | Improved glycaemic control and diabetic complications Improved malnutrition Bioactives, including ACE inhibitor Deleterious effect on bone mineralisation and strength |
Human clinical data needed Scalability and consistency of production More bone health studies needed |
| Myco- protein |
9 | 1.0 [129] |
Improved myofibrillar protein synthesis and gene expression Stimulated post exercise tissue remodelling Comparable to milk, fish and meat protein for glycaemic control Improved satiety Improved total and LDL cholesterol, lipid metabolism Slower, sustained amino acid release |
Larger cohorts needed to confirm effects |
| Nuts | 0 | 0.22 (almonds) 0.81 (roasted pistachios) (rat bioassay) [130] |
Improved cognition and memory (walnuts, pine nuts) Bioactives (antioxidant, antihypertensive, antiinflammation) |
Human clinical data needed. Low-moderate PDCAAS scores. |
| Oil Seeds | 3 | 0.5–0.6 (hemp seed) (rat bioassay) [131] | Improved hypoglycaemic response (canola/rapeseed) Improved hypotensive response (hemp seed, sesame seeds) Improved satiety Improved cholesterol (sesame seed) Improved antioxidant capacity |
More human studies needed. |
| Legumes, Beans | 3 (in mixed legume diet) | Fava bean 0.56 [126] Cooked beans 0.54–0.75 Extruded beans 0.58–0.69 Baked beans 0.47–0.66 ** [132] |
Improved satiety Reduced inflammatory cytokines (CRP, IL6, TNFα) |
Specific clinical studies on bean proteins not available. More human studies required |
| Legumes, Peas | 14 | Yellow pea 0.59 [126] Cooked (0.69–0.72) Extruded (0.65–0.73) Baked (0.69–0.75) [132] |
Improved satiety Reduced postprandial diastolic blood pressure (pea protein isolate) and systolic blood pressure in longer term (hydrolysate) Reduced postprandial blood glucose and HbA1c (hydrolysate) Reduced inflammatory cytokines (CRP, IL6, TNFα) |
Lack of consistency in satiety and blood glucose outcomes. More studies required to confirm effects on blood pressure and inflammatory biomarkers |
| Legumes, Lentils | 3 | 0.68–0.80 [123] | Improved satiety Reduced postprandial blood glucose Heme-iron absorption maintained Reduced inflammatory cytokines (CRP, IL6, TNFα) |
Limited clinical data available on lentil proteins |
| Legumes, Chickpeas | 1 | 0.69–0.77 [123] | Reduced inflammatory cytokines (CRP, IL6, TNFα) | No clinical data on purified chickpea proteins |
| Legumes, Lupin | 7 | 0.6 [133] | Improved hyperglycaemia (conglutin) Reduced LDL cholesterol and LDL:HDL ratio, especially in hypercholesterolemic subjects Reduced PCSK9 expression (improve lipid and cholesterol management) Reduced inflammatory cytokines and Th1-cell activation Increased antioxidant capacity of PBMCs |
Insufficient clinical data available on glycaemic and immune responses |
* Protein Digestibility Corrected Amino Acid Score (PDCAAS) is a method of evaluating the quality of a protein based on both the amino acid requirements of humans and their ability to digest it. ** Values dependent on variety; (ACE, angiotensin-I converting enzyme; CRP, C-reactive protein; DPP-IV, dipeptidyl-peptidase 4; HbA1c, glycated haemoglobin; HDL, high density lipoprotein; IL6, interleukin 6; LDL, low density lipoprotein; NAFLD, non-alcoholic fatty liver disease; PBMCs, peripheral blood mononuclear cells; PCSK9, Proprotein convertase subtilisin/kexin type 9; TNF, tumor necrosis factor).