Editing Microwave oven (section)

=== Effects on food and nutrients ===

Any form of cooking diminishes overall nutrient content in food, particularly [[water-soluble]] [[vitamin]]s common in vegetables, but the key variables are how much water is used in the cooking, how long the food is cooked, and at what temperature.<ref name=harvard-med>{{cite web |title=Microwave cooking and nutrition |date=February 6, 2019 |series=Family Health Guide |publisher=[[Harvard Medical School]] |website=health.harvard.edu |url=http://www.health.harvard.edu/fhg/updates/Microwave-cooking-and-nutrition.shtml |access-date=April 13, 2021 |archive-url=https://web.archive.org/web/20110717050842/http://www.health.harvard.edu/fhg/updates/Microwave-cooking-and-nutrition.shtml |archive-date=July 17, 2011 }}</ref><ref name=NYTimes>{{cite news |first=Anahad |last=O'Connor |date=October 17, 2006 |newspaper=[[The New York Times]] |title=The claim: Microwave ovens kill nutrients in food |url=https://www.nytimes.com/2006/10/17/health/17real.html|access-date=April 13, 2021}}</ref> Nutrients are primarily lost by leaching into cooking water, which tends to make microwave cooking effective, given the shorter cooking times it requires and that the water heated is in the food.<ref name="harvard">{{cite web|title=Microwave cooking and nutrition|url=http://www.health.harvard.edu/fhg/updates/Microwave-cooking-and-nutrition.shtml|work=Family Health Guide|publisher=Harvard Medical School|date=February 6, 2019|access-date=April 13, 2021|archive-url=https://web.archive.org/web/20110717050842/http://www.health.harvard.edu/fhg/updates/Microwave-cooking-and-nutrition.shtml|archive-date=July 17, 2011}}</ref> Like other heating methods, microwaving converts [[vitamin B12|vitamin B{{sub|12}}]] from an active to inactive form; the amount of conversion depends on the temperature reached, as well as the cooking time. Boiled food reaches a maximum of {{convert|100|Celsius}} (the boiling point of water), whereas microwaved food can get internally hotter than this, leading to faster breakdown of vitamin B{{sub|12}}.{{citation needed|date=April 2021}} The higher rate of loss is partially offset by the shorter cooking times required.<ref name=pmid10554220>{{cite journal |first1=Fumio |last1=Watanabe |first2=Katsuo |last2=Abe |first3=Tomoyuki |last3=Fujita |first4=Mashahiro |last4=Goto |first5=Miki |last5=Hiemori |first6=Yoshihisa |last6=Nakano |date=January 1998|title=Effects of microwave heating on the loss of vitamin B(12) in foods |journal=Journal of Agricultural and Food Chemistry |volume=46 |issue=1 |pages=206–210 |pmid=10554220 |doi=10.1021/jf970670x |bibcode=1998JAFC...46..206W |s2cid=23096987 }}</ref>

Spinach retains nearly all its [[folate]] when cooked in a microwave oven; when boiled, it loses about 77%, leaching nutrients into the cooking water.<ref name=harvard/> Bacon cooked by microwave oven has significantly lower levels of [[nitrosamine]]s than conventionally cooked bacon.<ref name=NYTimes/> Steamed vegetables tend to maintain more nutrients when microwaved than when cooked on a stovetop.<ref name="NYTimes"/> Microwave [[blanching (cooking)|blanching]] is 3–4&nbsp;times more effective than boiled-water blanching for retaining of the water-soluble vitamins, folate, [[thiamin]] and [[riboflavin]], with the exception of {{nobr|[[vitamin C]],}}  of which 29% is lost (compared with a 16% loss with boiled-water blanching).<ref>{{cite web |first1=M.A. |last1=Osinboyejo |first2=L.T. |last2= Walker |first3=S. |last3=Ogutu |first4=M. |last4=Verghese |title=Effects of microwave blanching vs. boiling water blanching on retention of selected water-soluble vitamins in turnips, foods, and greens using HPLC |series=National Center for Home Food Preservation |publisher=[[University of Georgia]] |url=http://www.uga.edu/nchfp/papers/2003/03iftturnipgreensposter.html |date=July 15, 2003 |access-date=July 23, 2011 }}</ref>