Disclaimer - While Vitamin U has been shown to have value as a nutrient, it has not been approved by the FDA as a treatment for any disease. Talk to your doctor or dietitian about your medical condition.
Vitamin U may help combat the ulcergenic effects of NSAIDs
Vitamin U is a mucin secretagogue
In the human body, Vitamin U heals and protects against peptic ulcers. It does so by stimulating the secretion of mucins onto the walls of the digestive tract, acting as a precursor to the biosynthesis of the master antioxidant glutathione, and supplies methyl groups for gene regulation, polyamine biosynthesis and a range of other molecules. Of these three functions, stimulating mucin secretion is the most direct way in which Vitamin U works.
In the stomach, there is an alkaline mucous bilayer gel that protects the stomach from gastric acid, pepsin digestion and bacterial infection. Mucus consists of two layers - a deep gel-like layer attached to cells and a superficial loosely-attached layer on top. The proteins that make up mucus are called mucins (MUC1, MUC5AC, MUC6), which are heavily-glycosylated proteins that attract water, thereby forming a gel. Mucins are made in foveolar cells lining the stomach and are stored in vesicles awaiting summons to the lumen. At the surface, some mucins stay attached to the cells and act as an anchor for the loosely-bound mucins to attach by disulfide bonds. When this mucous bilayer is disrupted, gastric juice can reach the lining of the stomach causing irritation and inflammation. Left long enough, a peptic ulcer may form.
Your body has a number of different ways to stimulate the secretion of mucin. The molecules that trigger secretion are called mucin secretagogues. The prime mucin secretagogue is prostaglandin E2, a hormone-like molecule that has many functions in the human body. It has a protective role in stomach function, suppressing production of gastric acid and pepsin, while at the same time promoting secretion of mucin and the alkaline molecule bicarbonate (Park et al). NSAIDs reduce prostaglandin E2 synthesis by inhibiting COX-1, leading to less mucin, less protection and a greater risk of ulcers.
Food sources of Vitamin U
In general, vegetables belonging to the Brassicacea family are the best source of Vitamin U. This family includes cabbages, kale, broccoli, kohlrabi, collards and turnips. Other vegetables such as spinach, asparagus and celery also produce abundant amounts of Vitamin U. Fruit are also good sources, but not as good as vegetables. In general, there is more Vitamin U in the leaves and stalks than in the fruit, roots and seeds. Grains seem to have little when fresh, but Vitamin U is made during sprouting. Animal products have little to no Vitamin U as it is not synthesized nor stored in significant amounts in animals.
Several studies have measured the concentration of Vitamin U in various foods. Tables listing some of these results are included below. Many factors affect the amount of Vitamin U in a given vegetable. These factors include storage conditions, storage duration, harvest time, regional variations and species variations. For example, cabbages have more Vitamin U during spring and summer when freshly harvested, with the nutrient slowly degrading with storage. After six months in the fridge, the concentration drops by one third, with faster losses at room temperature. In contrast, when barley is germinated for making beer, the amount of Vitamin U rises over time, affecting the flavor of the end product. In some cases, there are varieties of fruit that produce less Vitamin U. Oranges that have been selected to produce less Vitamin U are used to make juice because Vitamin U breaks down with extended storage and pasteurisation to form dimethyl sulfide, a compound that negatively affects the taste of the product (Sakamoto et al https://pubmed.ncbi.nlm.nih.gov/8987599/.)
Song, Ji-Hoon, Hae-Rim Lee, and Soon-Mi Shim. 2016. “Determination of S-Methyl-L-Methionine (SMM) from Brassicaceae Family Vegetables and Characterization of the Intestinal Transport of SMM by Caco-2 Cells.” Journal of Food Science 82 (1): 36–43.
https://www.ncbi.nlm.nih.gov/pubmed/27883364
Food (Vitamin U concentration (mg/kg dry weight))
Radish (129-139)
Cabbage (535)
Kimchi cabbage (89-116)
Broccoli (150-350)
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https://www.ncbi.nlm.nih.gov/pubmed/19754146
Food (Vitamin U concentration (mg/kg wet weight))
Celery (176)
Kohlrabi (124)
Leek (94)
Beetroot (89)
Cabbage (81)
White asparagus - Peru spears (161)
White asparagus - Peru stalks (86)
White asparagus - Germany spears (252)
White asparagus - Germany stalks (68)
White asparagus - Greece spears (113)
White asparagus - Greece stalks (101)
Green asparagus - Peru spears (234)
Green asparagus - Peru stalks (109)
Green asparagus - Germany spears (94)
Green asparagus - Germany stalks (53)
Green asparagus - Mexico spears (134)
Green asparagus - Mexico stalks (64)
Tomato (2.8)
Commercial orange juice (0.9)
Commercial strawberry juice (1.8)
Barley - unprocessed (0.9)
Barley - after 4 days of germination (24)
Kim, G.-H. Determination of Vitamin U in Food Plants. Food Sci. Technol. Res. 9, 316–319 (2003).
https://www.jstage.jst.go.jp/article/fstr/9/4/9_4_316/_pdf
Food (Vitamin U concentration (mg/100g dry weight))
Spinach (45.2)
Pak-choy (34.3)
Kale (23.4)
Leaf mustard (19.6)
Bud of aralia (19.3)
Broccoli (18.9)
Asparagus (18.7)
Sanmanul - a wild garlic (14.4)
Crown daisy (11.1)
Burdock (11.0)
Celery (8.3)
Komchi (4.7)
Wasabi (4.7)
Chamchi - a wild korean plant (4.0)
Shepherd’s purse (3.4)
Garlic (2.8)
Onion (2.7)
Green onion (2.6)
Laver (2.2)
Nurukchi (0.8)
Green tea (0.1)
Ginger (not detected)
Seaweed (not detected)
Red chilli (not detected)
Miscellaneous wild korean vegetables (not detected)
Kovatscheva, E. G. & Popova, J. G. [S-Methylmethionine content in plant and animal tissues and stability during storage]. Nahrung 21, 465–472 (1977).
Food (Vitamin U concentration (mg/kg wet weight))
Cabbage (50-104)
Kohlrabi (81-110)
Tomato (45-83)
Garlic leaves (44-64)
Raspberries (27)
Strawberries (14-25)
How much Vitamin U do you need to heal ulcers?
In 2003, Kim reported 26-46 mg/100 g of dry weight, which given that a cabbage is ~92% water, works out as 21-37 mg/kg of fresh cabbage. In 2009, Scherb and others found that cabbages have 81 mg of Vitamin U per kg of fresh cabbage. In 2017, Song et al determined that cabbages contain 50 mg/kg of Vitamin U. So we can estimate that there is roughly 21-81 mg Vitamin U per kg of cabbage.
1 liter of juice is typically extracted from about 2 kg of cabbage. Cheney arrived at 1 liter from prior studies in which various volumes of cabbage juice were given to guinea pigs subjected to chemically-induced ulceration. 100% of the guinea pigs responded to the guinea-pig equivalent of 720 ml of juice. The volume used in the clinical study was rounded up to 1 liter to take into consideration variations in body weight and unexpected factors.
Issues with drinking 1 liter of cabbage juice
Many people find cabbage juice to be distasteful. The chemicals responsible for this bitterness are called isothiocyanates. These compounds are produced in the cabbage when the leaves are physically damaged during chewing or juicing. Glucosinolates are enzymatically converted by myrosinases to form the bitter isothiocyanates. Some people are lucky in that can't taste isothiocyanates all that well so they can readily drink cabbage juice. One way to prevent the formation of isothiocyanates is by boiling unbroken cabbage leaves before juicing to kill the enzymes. That's why boiled cabbage has a mild taste compared to raw cabbage. However, the problem with this approach is that Vitamin U is also unstable to boiling, negating any beneficial effects.
Gas
A second issue is gas. Cabbage has a significant amount of raffinose, a sugar that is notorious for producing gas when eaten. The human small intestine lacks the enzyme required for the digestion of raffinose. Unfortunately, some types of bacteria in our large intestine do have such an enzyme and will ferment raffinose quite readily to form gases. These gases produced in the colon have only one way out and will cause bloating and discomfort until discharged. Ingesting one liter of cabbage juice will cause problems for most people. In principle, a possible solution is to treat the cabbage juice with Beano before drinking it. Beano is basically alpha-galactosidase, an enzyme that will break down raffinose into sucrose and galactose, both of which we can easily break down and absorb. I'm not sure whether anyone has tested this idea, though taking Beano along with the juice as recommended should help. Drinking several cups spread throughout the day should also reduce bloating.
Smell
A third issue is smell. Fresh cabbage juice smells fine - old juice does not. Vitamin U is degraded to homoserine and dimethylsulfide by enzymes found in cabbage. Dimethylsulfide has a disagreeable sulfur odor a little like that found in rotten eggs, though without the toxicity. These enzymes don't work as quickly as myrosinases, but leaving cabbage juice sitting around for a few hours will allow plenty of time for dimethylsulfide to form. Putting the juice in the fridge will slow the reaction somewhat, but after 24 h the juice still tastes terrible. Even if a person could stomach the old juice, there would not be much point as by this stage most of the Vitamin U would have been degraded. Cabbages also have other compounds that contain sulfur that when broken down produce disagreeable odors. The solution is to drink cabbage juice fresh before it has had a chance to go off.
Cabbage Juice Heals Peptic Ulcers
Why do we get ulcers? Ulcers result from an imbalance in the digestive system between protective and destructive factors. An alkaline bilayer of mucus containing mucin protects the wall of the digestive tract from harsh elements such as stomach acid, infection by bacteria living in the digestive system, NSAIDs, and dietary factors like high salt and alcohol. In modern times, NSAIDs increasingly contribute to ulcer formation by inhibiting the mucus-stimulating function of our body's prostaglandins. When the mucus layer is depleted, these harsh elements irritate the epithelial cells lining the digestive tract causing inflammation and enabling deep infection.
Ulcers are usually treated with proton pump inhibitors or H2 blockers to reduce acid production, antibiotics to treat bacterial infections (particularly Helicobacter pylori in the stomach), antacids to neutralize acid, and mucosal protectants such as prostaglandin mimics. Unfortunately, these only provide a temporary solution to the problem. Ulcers return soon after cessation of treatment. Excessive stomach acid is usually not the root problem, nor is H. pylori infection. Most people with ulcers produce a normal amount of stomach acid, and half the world's population has H. pylori yet remain ulcer-free. These facts indicate that while acid and infection contribute to the formation of ulcers, other factors are at play.
Given the findings of Dr Cheney, it's easy to see that eating a balanced diet rich in sources of Vitamin U is beneficial. But how does Vitamin U work? In later studies, it was shown that Vitamin U has three properties that help maintain a healthy gut.
- Stimulating the release of mucin into the mucus layer, thereby protecting the walls from acid and bacterial infection (most important).
- Reducing inflammation by acting as a precursor to glutathione, the master antioxidant of the human body via its conversion to cysteine.
- Coordinating with other nutrients such as methionine, folate, B12, betaine, choline, SAMe and B6 to supply vital methyl groups required for optimal health.
Increasing the Vitamin U content of one's diet in combination with reducing the intake of foods that deplete the protective mucus layer has been shown to improve ulcerative conditions in the digestive system. A diet rich in fresh vegetables, vegetable juice and fruit, and low in salt, alcohol and sugars is a good approach for restoring the mucus bilayer in most patients.
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