- Crusty food like bread or toast
- Crispy food like chips
- Salty food like pretzels
- Sweet food like candy
- Sticky food like cookies
- Sour food like vinegar
- Hot food like coffee
Summary - H2 blockers are drugs used to reduce stomach acid in people who have pain due to stomach ulcers. Vitamin U in the form of fresh vegetable juice or supplements can be used alongside H2 blockers to speed up the restoration of the protective mucous bilayer.
The human stomach is a very acidic environment. The pH of a correctly-functioning stomach is 1.5 - 3. The acidity of gastric juice is due to hydrochloric acid (HCl), which is produced by parietal cells in the upper parts of the stomach (fundus and cardia). Parietal cells produce acid using enzymes called proton pumps (H+/K+ ATPase), which use the energy derived from the hydrolysis of ATP to pump H+ into the stomach. It is the protons (H+) that cause acidity.
The parietal cells pump acid into the stomach in response to signal molecules binding receptors. There are numerous kinds of receptors that respond to different stimuli, either positively or negatively. The most important for acid production are the H2 histamine receptors. Protein in food is broken down in the stomach by acid and the enzyme pepsin to form peptides. These peptides stimulate the release of the hormone gastrin from G cells in the stomach and duodenum. Gastrin stimulates the release of histamine from ECL cells. Histamine binds receptors in the base of parietal cells where it stimulates the movement of proton pumps to the apical surface, where they pump acid into the stomach cavity (lumen). This acid accelerates this whole cycle, breaking down more proteins in food by hydrolysis as well as activating pepsin.
H2 blockers bind to the H2 receptors, which stops histamine from binding. If histamine can't bind, the levels of acid in the stomach remain fairly low and the corresponding pH relatively high. (H2 blockers are often referred to as H2 antagonists because they block the binding of histamine without itself stimulating the function of the receptor, an important distinction from agonists).
H2 blockers were invented in the 1960s and have to a large extent been superseded by proton pump inhibitors due to the latter's more potent acid-suppressing abilities. Commonly used H2 blockers include omeprazole (e.g. Prilosec), famotidine (e.g. Pepcid) and cimetidine (e.g. Tagamet). Ranitidine (e.g. Zantac) was the most prescribed drug in the US during the 1980s, but the FDA has recently banned its sale due to carcinogenic impurities.
Stomach ulcers and gastroesophageal reflux (GERD) are conditions characterized by pain caused by stomach acid coming into direct contact with the lining of the stomach and esophagus, respectively. Contrary to popular opinion, these conditions are rarely caused by excessive production of stomach acid. In fact, the acidity in the stomach of those with stomach ulcers is typically low (i.e. relatively high pH). GERD is caused by normal stomach acid coming into contact with the esophagus, an organ that is not designed to withstand such exposure. Unlike the stomach, the esophagus is not coated with a protective alkaline mucous bilayer and is very sensitive to contact from even small amounts of gastric juice.
One unfortunate problem with taking H2 blockers for stomach ulcers is that they reduce the secretion of mucin (Ichikawa et al., Diebel et al). So while they reduce pain by reducing the amount of acid produced, they also increase the risk of pain by weakening the mucous bilayer.
Vitamin U is a nutrient abundant in vegetables and fruit that stimulates the secretion of mucin in the stomach. As fresh vegetables and fruit have been a major component of our diet for a very long time, it is reasonable to conclude that dietary Vitamin U plays an important role in the maintenance of optimal stomach function.
Can Vitamin U be combined with H2 blockers?
Considering Vitamin U stimulates mucin secretion and H2 blocker reduce it, one may wonder whether Vitamin U can be taken with H2 blockers to negate the negative effects. The evidence suggests yes. In 2009, Ichikawa et al. showed that co-administration of Vitamin U with famotidine reversed the mucin-blocking effects of famotidine without affecting the acid-suppression effects. These results suggest that Vitamin U can add another level of protection to the gut in those taking H2 blockers.
Summary - Vitamin U is a nutrient abundant in vegetables and fruit whose main function is to stimulate the secretion of mucin and enable the formation of the mucous bilayer that protects the stomach from acid and Helicobacter pylori.
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.
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.