Ralph Moss

Harry Hirsute · � #1 � 02-10-2008, 04:36 PM

Quote:

Cornell scientists, led by Dr. R.H. Liu, compared the phenolic and flavonoid content of 10 varieties of onion that are commonly available in the United States, as well as shallots. The ten varieties were as follows:

1. Empire Sweet
2. Imperial Valley Sweet; and
3. Mexico
4. New York Bold
5. Northern Red
6. Peruvian Sweet
7. Texas 1015
8. Vidalia
9. Western White
10. Western Yellow

These were evaluated for their total phenolic and flavonoid content as well as their antioxidant and antiproliferative (i.e., anticancer) activity.

Shallots had the highest total phenolic content among all the varieties tested, with a 6-fold difference observed when compared to Vidalia onions.

Western Yellows exhibited the highest total flavonoid content of all the onion varieties tested, with an 11-fold difference when compared to the phenol-poor Western Whites. Shallots exhibited the highest total antioxidant activity.

Leaving aside the antioxidant-rich shallots, the onions were ranked as follows for antioxidant activity:

1. Western Yellow
2. New York Bold
3. Northern Red
4. Mexico
5. Empire Sweet
6. Western White
7. Peruvian Sweet
8. Texas 1015
9. Imperial Valley Sweet
10. Vidalia

The Cornell scientists also exposed various cancer cell lines to these onion varieties to see what effect the onions had on cell proliferation. The most effective of all in inhibiting cancer cells were - again - shallots, followed by New York Bold, Western Yellow and Northern Reds. The rest of the varieties all demonstrated weak anti-proliferative activity against these cancer cell lines.

"These results may influence consumers toward purchasing onion varieties exhibiting greater potential health benefits," the authors wrote.

I know these results will influence my own shopping habits. The next time I purchase onions I will be looking for Western Yellow, New York Bold and/or Northern Red (a particularly good variety for salads).

I will also get some shallots when my budget can afford them and they look nice and plump. Sweet onions, such as Vidalias or Maya, are indeed delicious and relatively inexpensive. But they simply do not convey a fraction of the health benefits of yellow or red onions, or of shallots.

https://www.cancerdecisions.com/021008.html

scorpiotiger · � #2 � 02-10-2008, 08:59 PM

I use the yellow onions all the time, the Spanish Onions? I wonder if they are the ones that are mentioned here?

I like the red ones for salads, too. and, according to iggy, the skins make great soup. right, iggy?

Harry Hirsute · � #3 � 02-11-2008, 01:13 AM

Quote:

Originally Posted by scorpiotiger

I use the yellow onions all the time, the Spanish Onions? I wonder if they are the ones that are mentioned here?

I believe that the yellow color (in onions) is indicative of a higher quercetin content. Quercetin supplements have a pronounced yellow color to them.

Music, however, does not contain quercetin ... even if it's called Yellow https://youtube.com/watch?v=hjYeDh7Qkqs

Iggy Dalrymple · � #4 � 02-15-2008, 11:51 AM

I was told on another forum that quercetin was not very bio-available unless I used a special water soluble form called quercetin chalcone. I wonder how true this is. I've been dissolving quercetin, lecithin, resveratrol, lycopene, curcumin, and genistein in hot distilled water and hot coconut oil. I mix that with my oatmeal.

Dr Steve, at Grouppe Kurosawa, advises dissolving resveratrol in diluted vodka.

Harry Hirsute · � #5 � 02-15-2008, 12:20 PM

Well, it seems as if ingesting quercetin with some fat helps with the bioavailability:

Quote:

The flavonol quercetin is one of the most prevalent flavonoids found in edible plants. In this study, the influence of dietary fat on oral bioavailability of quercetin was investigated.

Quercetin (30 �mol/kg body weight) was administered either as the lipophilic aglycone or as the more hydrophilic quercetin-3-O-glucoside in test meals differing in fat content (3, 17, or 32 g fat/100 g diet) to growing pigs.

Blood samples were drawn repeatedly over a 24-h period and analyzed by HPLC. The main metabolite found in plasma was always conjugated quercetin.

Quercetin bioavailability from each diet was always higher from the glucoside than from the aglycone.

Irrespective of the chemical form applied, the bioavailability of quercetin was higher in the 17% fat diet compared with the 3% fat diet (P < 0.05). No further effect on bioavailability was observed when the flavonols were administered with diets containing 32% fat.

The elimination of quercetin was significantly delayed after its application with fat-enriched diets (P < 0.05).

Thus, in addition to the chemical form of the flavonol, the fat content of the diet influences oral bioavailability of quercetin.

https://jn.nutrition.org/cgi/content/full/134/6/1508

Quercetin (in foods) is somewhat bioavailable (even without mention of the form of quercetin or fat-intake):

Quote:

Abstract: Berries are a rich source of various polyphenols, including the flavonoid quercetin. In this article, the results of three intervention studies investigating the bioavailability of quercetin from berries are reviewed.

In the first study, we investigated the short-term kinetics of quercetin after consumption of black currant juice and showed that quercetin is rapidly absorbed from it.

In the second study, we showed that plasma quercetin levels increase up to 50% in subjects consuming 100 g/day of bilberries, black currants, and lingonberries as a part of their normal diets for 2 mo. In the third study, healthy subjects consumed a diet high or low in vegetables, berries, and other fruit for 6 wk.

Quercetin concentrations nearly doubled in the high-vegetable, -berry, and -other fruit group and decreased by 30% in subjects consuming less of these foods than normally.

The results showed that plasma quercetin is bioavailable from a diet containing berries and indicate that it may be a good biomarker of fruit and vegetable intake in general.

https://www.leaonline.com/doi/abs/10....327914nc5401_3

Apples also appear to be a good source of bioavailable quercetin:

Quote:

Quercetin is a strong antioxidant and a major dietary flavonoid. Epidemiological studies suggest that consumption of quercetin protects against cardiovascular disease, but its absorption in man is controversial.

We fed nine subjects a single large dose of onions, which contain glucose conjugates of quercetin, apples, which contain both glucose and non-glucose quercetin glycosides, or pure quercetin-3-rutinoside, the major quercetin glycoside in tea. Plasma levels were then measured over 36 h.

Bioavailability of quercetin from apples and of pure quercetin rutinoside was both 30% relative to onions. Peak levels were achieved less than 0.7 h after ingestion of onions, 2.5 h after apples and 9 h after the rutinoside. Half-lives of elimination were 28 h for onions and 23 h for apples.

We conclude that conjugation with glucose enhances absorption from the small gut. Because of the long half-lives of elimination, repeated consumption of quercetin-containing foods will cause accumulation of quercetin in blood.

https://www.sciencedirect.com/science...201ee93216b30d

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