Jump to content

Whey protein: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
No edit summary
No edit summary
Line 41: Line 41:


==Major forms==
==Major forms==
Whey protein typically comes in three major forms: [[concentrate]], [[Whey_Protein_Isolate|isolate]], and [[Hydrolyzed collagen (hydrolysate)|hydrolysate]].
Whey protein typically comes in three major forms: [[concentrate]] (WPC), [[Whey_Protein_Isolate|isolate]] (WPI), and [[hydrosylate]] (WPH).
*Concentrates contain a low level of fat and [[cholesterol]] but, in general, have higher levels of [[Biological activity|bioactive]] compounds, and carbohydrates in the form of [[lactose]] — they are 29%–89% protein by weight.
*Concentrates typically a low (but still significant) level of fat [[cholesterol]] but, in general, have higher levels of [[Biological activity|bioactive]] compounds, and carbohydrates in the form of [[lactose]] — they are 29%–89% protein by weight.
*Isolates are processed to remove the fat, and lactose, but are usually lower in bioactivated compounds as well — they are 90%+ protein by weight. Both of these types are mild to slightly milky in taste.
*Isolates are processed to remove the fat, and lactose, but are usually lower in bioactivated compounds as well — they are 90%+ protein by weight. Both WPC and WPI are mild to slightly milky in taste.
*Hydrolysates are whey proteins that are predigested and partially [[hydrolysis|hydrolyzed]] for the purpose of easier metabolizing, but their cost is generally higher.<ref name=Foegeding/> Highly-hydrolysed whey may be less [[allergen]]ic than other forms of whey.<ref name=Lee>{{cite journal |author=Lee YH |title=Food-processing approaches to altering allergenic potential of milk-based formula |journal=J. Pediatr. |volume=121 |issue=5 Pt 2 |pages=S47–50 |year=1992 |month=November |pmid=1447634 |doi=10.1016/S0022-3476(05)81406-4}}</ref>
*Hydrolysates are whey proteins that are predigested and partially [[hydrolysis|hydrolyzed]] for the purpose of easier metabolizing, but their cost is generally higher.<ref name=Foegeding/> Highly-hydrolysed whey may be less [[allergen]]ic than other forms of whey.<ref name=Lee>{{cite journal |author=Lee YH |title=Food-processing approaches to altering allergenic potential of milk-based formula |journal=J. Pediatr. |volume=121 |issue=5 Pt 2 |pages=S47–50 |year=1992 |month=November |pmid=1447634 |doi=10.1016/S0022-3476(05)81406-4}}</ref>


Line 57: Line 57:
A significant portion of the population experiences severe digestive issues following consumption of whey protein powder. These may include gas, bloating, cramps, tiredness, weakness, fatigue, headaches, and irritability. The cause of these digestive problems has not yet been determined, but is reported frequently on strength training forums.
A significant portion of the population experiences severe digestive issues following consumption of whey protein powder. These may include gas, bloating, cramps, tiredness, weakness, fatigue, headaches, and irritability. The cause of these digestive problems has not yet been determined, but is reported frequently on strength training forums.


It should be noted that similar symptoms can be caused by ingredients found in lower quality protein powders such as [[lactose]] in whey protein concentrate or [[artificial sweeteners]] in most commercial protein powders. The effects of these substances can be distinguished from the effects of whey alone by switching to an unsweetened whey isolate or hydrosylate. If symptoms are not eliminated by switching to a more pure form of whey protein, many alternative powders, such as [[pea protein]]] or [[rice protein]] may be suggested.
It should be noted that similar symptoms can be caused by ingredients found in lower quality protein powders such as [[lactose]] in whey protein concentrate or [[artificial sweeteners]] in most commercial protein powders. The effects of these substances can be distinguished from the effects of whey alone by switching to an unsweetened whey isolate or hydrosylate. If symptoms are not eliminated by switching to a more pure form of whey protein, many alternative powders, such as [[pea protein]] or [[rice protein]] may be suggested.


==References==
==References==

Revision as of 18:47, 17 October 2011

Containers of whey protein being sold at a health food store.

Whey protein is a mixture of globular proteins isolated from whey, the liquid material created as a by-product of cheese production. Some preclinical studies in rodents have suggested that whey protein may possess anti-inflammatory or anti-cancer properties; however, human data is lacking.[1][2] The effects of whey protein on human health are of great interest and are currently being investigated as a way of reducing disease risk, as well as a possible supplementary treatment for several diseases.[3]

Whey protein is commonly marketed and ingested as a dietary supplement, and various health claims have been attributed to it in the alternative medicine community.[4] Although whey proteins are responsible for some milk allergies, the major allergens in milk are the caseins.[5][6]

Production

Main article: Whey

Whey is left over when milk coagulates and contains everything that is soluble from milk. It is a 5% solution of lactose in water, with some minerals and lactalbumin.[7] It is removed after cheese is processed. The fat is removed and then is processed for human foods.[7] Processing can be done by simple drying, or the protein content can be increased by removing lipids and other non-protein materials.[8] For example, spray drying after membrane filtration separates the proteins from whey.[9]

Whey can be denatured by heat. High heat (such as the sustained high temperatures above 72 °C associated with the pasteurization process) denatures whey proteins. While native whey protein does not aggregate upon renneting or acidification of milk, denaturing the whey protein triggers hydrophobic interactions with other proteins, and the formation of a protein gel.[8] Heat-denatured whey can still cause allergies in some people.[10]

Composition

Whey protein is the collection of globular proteins isolated from whey, a by-product of cheese manufactured from cow's milk. The protein in cow's milk is 20% whey protein and 80% casein protein,[11] whereas the protein in human milk is 60% whey and 40% casein.[12] Whey protein is typically a mixture of beta-lactoglobulin (~65%), alpha-lactalbumin (~25%), and serum albumin (~8%), which are soluble in their native forms, independent of pH. The protein fraction in whey (approximately 10% of the total dry solids within whey) comprises four major protein fractions and six minor protein fractions. The major protein fractions in whey are beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, and immunoglobulins.[13]

Major forms

Whey protein typically comes in three major forms: concentrate (WPC), isolate (WPI), and hydrosylate (WPH).

  • Concentrates typically a low (but still significant) level of fat cholesterol but, in general, have higher levels of bioactive compounds, and carbohydrates in the form of lactose — they are 29%–89% protein by weight.
  • Isolates are processed to remove the fat, and lactose, but are usually lower in bioactivated compounds as well — they are 90%+ protein by weight. Both WPC and WPI are mild to slightly milky in taste.
  • Hydrolysates are whey proteins that are predigested and partially hydrolyzed for the purpose of easier metabolizing, but their cost is generally higher.[8] Highly-hydrolysed whey may be less allergenic than other forms of whey.[10]

Benefits for muscle building

Research indicates that the use of supplementary whey or soy protein combined with resistance training offers some benefit over no protein supplementation.[14] However, the timing of protein supplement ingestion may not have any significant effects on strength, power, or body-composition.[15]

Health effects

The use of whey protein as a source of amino acids and its effect on reducing the risks of diseases such as heart disease and cancer is the focus of ongoing research.[3] Whey is an abundant source of branched-chain amino acids (BCAAs),[16] which are used to fuel working muscles and stimulate protein synthesis.[17] In particular, leucine plays a key role in initiating the transcription pathway that fires up protein synthesis.[18] When leucine is ingested in high amounts, such as with whey protein supplementation, there is greater stimulation of protein synthesis, which may speed recovery and adaptation to stress (exercise).[19]

Whey protein contains the amino acid cysteine, which can be used to make glutathione. However, this amino acid is not essential for the synthesis of glutathione, and some studies have suggested that the amount of cysteine in the diet may have little effect on glutathione synthesis.[20] However, another study suggested that large amounts of whey protein can increase cellular glutathione levels.[21] Glutathione is an antioxidant that defends the body against free radical damage and some toxins, and studies in animals have suggested that milk proteins might reduce the risk of cancer.[22]

Digestive Issues

A significant portion of the population experiences severe digestive issues following consumption of whey protein powder. These may include gas, bloating, cramps, tiredness, weakness, fatigue, headaches, and irritability. The cause of these digestive problems has not yet been determined, but is reported frequently on strength training forums.

It should be noted that similar symptoms can be caused by ingredients found in lower quality protein powders such as lactose in whey protein concentrate or artificial sweeteners in most commercial protein powders. The effects of these substances can be distinguished from the effects of whey alone by switching to an unsweetened whey isolate or hydrosylate. If symptoms are not eliminated by switching to a more pure form of whey protein, many alternative powders, such as pea protein or rice protein may be suggested.

References

  1. ^ Hakkak R, Korourian S, Ronis MJ, Johnston JM, Badger TM (2001). "Dietary whey protein protects against azoxymethane-induced colon tumors in male rats". Cancer Epidemiol. Biomarkers Prev. 10 (5): 555–8. PMID 11352868. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  2. ^ Xiao R, Carter JA, Linz AL, Ferguson M, Badger TM, Simmen FA (2006). "Dietary whey protein lowers serum C-peptide concentration and duodenal SREBP-1c mRNA abundance, and reduces occurrence of duodenal tumors and colon aberrant crypt foci in azoxymethane-treated male rats". J. Nutr. Biochem. 17 (9): 626–34. doi:10.1016/j.jnutbio.2005.11.008. PMID 16504496. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  3. ^ a b Krissansen GW (2007). "Emerging health properties of whey proteins and their clinical implications". J Am Coll Nutr. 26 (6): 713S–23S. PMID 18187438. {{cite journal}}: Unknown parameter |month= ignored (help)
  4. ^ Marshall, K (2004). "Therapeutic applications of whey protein". Alternative Medicine Review. 9 (2): 136–156. PMID 15253675.
  5. ^ Wal JM (2004). "Bovine milk allergenicity". Ann. Allergy Asthma Immunol. 93 (5 Suppl 3): S2–11. doi:10.1016/S1081-1206(10)61726-7. PMID 15562868. {{cite journal}}: Unknown parameter |month= ignored (help)
  6. ^ Burks W, Helm R, Stanley S, Bannon GA (2001). "Food allergens". Curr Opin Allergy Clin Immunol. 1 (3): 243–8. PMID 11964696. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  7. ^ a b “Whey.” The Encyclopedia Britannica. 15th ed. 1994
  8. ^ a b c Foegeding, EA; Davis, JP; Doucet, D; McGuffey, MK (2002). "Advances in modifying and understanding whey protein functionality". Trends in Food Science & Technology. 13 (5): 151–9. doi:10.1016/S0924-2244(02)00111-5. {{cite journal}}: |access-date= requires |url= (help); More than one of |author= and |last1= specified (help)
  9. ^ Tunick MH (2008). "Whey Protein Production and Utilization.". In Onwulata CI, Huth PJ (ed.). Whey processing, functionality and health benefits (abstract). Ames, Iowa: Blackwell Publishing; IFT Press. pp. 1–13.
  10. ^ a b Lee YH (1992). "Food-processing approaches to altering allergenic potential of milk-based formula". J. Pediatr. 121 (5 Pt 2): S47–50. doi:10.1016/S0022-3476(05)81406-4. PMID 1447634. {{cite journal}}: Unknown parameter |month= ignored (help)
  11. ^ Jay R. Hoffman and Michael J. Falvo (2004). "Protein - Which is best?". Journal of Sports Science and Medicine (3): 118–130.
  12. ^ Luhovyy BL, Akhavan T, Anderson GH (2007). "Whey proteins in the regulation of food intake and satiety". JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION. 26 (6): 704S–712S. PMID 18187437.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  13. ^ Haug A, Høstmark AT, Harstad OM, A; Høstmark, AT; Harstad, OM (25 September 2007). "Bovine milk in human nutrition – a review". Lipids Health Dis. 6: 25. doi:10.1186/1476-511X-6-25. PMC 2039733. PMID 17894873.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: unflagged free DOI (link)
  14. ^ http://www.ncbi.nlm.nih.gov/pubmed/16948480
  15. ^ . PMID 19478342. {{cite journal}}: Cite journal requires |journal= (help); Missing or empty |title= (help)
  16. ^ Rieu I, Balage M, Sornet C; et al. (2007). "Increased availability of leucine with leucine-rich whey proteins improves postprandial muscle protein synthesis in aging rats". Nutrition. 23 (4): 323–31. doi:10.1016/j.nut.2006.12.013. PMID 17367997. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  17. ^ Kimball Scott; Jefferson, LS (2006). "Signaling Pathways and Molecular Mechanisms through which Branched-Chain Amino Acids Mediate Translational Control of Protein Synthesis". Journal of Nutrition. 136 (1): 227S. PMID 16365087. {{cite journal}}: More than one of |work= and |journal= specified (help)
  18. ^ Fujita, Dreyer, Drummon, Glynn, cadenas; et al. (2007). "Nutrient signalling in the regulation of human muscle protein synthesis". The Journal of physiology. 582 (Pt 2): 813–23. doi:10.1113/jphysiol.2007.134593. PMC 2075348. PMID 17478528. {{cite journal}}: Explicit use of et al. in: |author= (help); More than one of |work= and |journal= specified (help)CS1 maint: multiple names: authors list (link)
  19. ^ Ha E, Zemel MB (2003). "Functional properties of whey, whey components, and essential amino acids: mechanisms underlying health benefits for active people (review)". J. Nutr. Biochem. 14 (5): 251–8. doi:10.1016/S0955-2863(03)00030-5. PMID 12832028. {{cite journal}}: Unknown parameter |month= ignored (help)
  20. ^ Courtney-Martin G, Rafii M, Wykes LJ, Ball RO, Pencharz PB (2008). "Methionine-adequate cysteine-free diet does not limit erythrocyte glutathione synthesis in young healthy adult men". J. Nutr. 138 (11): 2172–8. doi:10.3945/jn.108.093302. PMID 18936215. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  21. ^ Zavorsky, Kubow, Grey, Riverin, Lands (2007). "An open-label dose-response study of lymphocyte glutathione levels in healthy men and women receiving pressurized whey protein isolate supplements". International Journal of Food Sciences and Nutrition. 58 (6): 429. doi:10.1080/09637480701253581. PMID 17710587. {{cite journal}}: More than one of |work= and |journal= specified (help)CS1 maint: multiple names: authors list (link)
  22. ^ P.W.Parodi. "A Role for Milk Proteins and their Peptides in Cancer Prevention". Current Pharmaceutical Design. 13 (8): 813–828. ISSN 1281-6128. {{cite journal}}: Check |issn= value (help)
Retrieved from "https://en.wikipedia.org/w/index.php?title=Whey_protein&oldid=456051076"