24 October, 2008

Excuse Me, That Gas Lowers My Blood Pressure

Dr. Solomon Snyder from Johns Hopkins determined that the embarrassing aroma of flatulence is caused by a gas which lowers blood pressure. The team at Johns Hopkins reported its conclusions in the October 24 edition of the journal ‘Science.’

Over the past twenty years, biologists have been intrigued by the properties of various gases (called gasotransmitters) in signaling a number of functions in the bodies of mammals. You may be familiar with some earlier work. Nitrous oxide is used by many cardiac patients. Gasotransmitters are common in mammals. Findings on the importance of hydrogen sulfide in mice, as this study reports, may have applications in human diseases, such as diabetes and neurodegenerative diseases.

Cells lining the blood vessels produce hydrogen sulfide (H2S). This gas produces the all-too-familiar rotten egg odor when a person breaks wind. This same gas seems to relax the walls of blood vessels, easing hypertension.

Dr. Snyder’s team genetically altered mice so that their cells did not produce an enzyme called cystathionine gamma-lyase (CSE). CSE deficient mice showed reduced H2S levels in their serum, heart, aorta, and other tissues. The non-chimera littermates had higher levels of H2S. The results confirmed the hypothesis that the enzyme was key in tissues’ production of H2S.

Modified mice showed significantly higher blood pressure comparable to serious hypertension in humans. They also had increased plasma homocysteine levels, suspected as a marker for inflammation and higher risk for cardiovascular disease. In addition, L-cysteine levels were lower in the chimera. L-cysteine plays a key role in the immune system and in protecting the liver. Both functions seem to be related to L-cysteine’s role in the production of glutathione. Glutathione levels were also lower in the genetically altered mice.

Scientists dosed the mice with a chemical called methacholine that relaxes normal blood vessels. The CSE-lacking mice’s blood vessels showed little change. Researchers concluded that hydrogen sulfide is a significant for regulating blood pressure.

The researchers note that all animal experiments were conducted in accordance with approved protocols by the Animal Health Care Committee of the University of Saskatchewan, Canada.

The study did not say that passing gas lowers blood pressure. Intestinal gas often indicates that foods have fermented in the colon instead of being completely digested.

Air, food, and liquids are moved through your digestive system by the contraction of muscles in the walls of your intestines.

There are two other ways in which gas can escape your intestine than release through the anus.

First, it can be absorbed across the lining of the intestine into your blood (perhaps aiding the effect the researchers above observed). The gas then travels in the blood and ultimately, if in excess, is excreted on your breath.

Second, gas can be removed and used by certain types of bacteria within the intestine. In fact, most of the gas that is formed by bacteria in the intestines is removed by other bacteria in the intestines.

Often, gas is eliminated at night as you sleep.

Three factors are often cited as causes for flatulence: swallowing air; improperly digested sugars and starches; and an imbalance of bacteria and fungus in the small intestine.

Small amounts of air are frequently swallowed. Eating too quickly and scanty chewing allow greater quantities of air to enter your digestive tract. Swallowed air is sometimes cited as a source of flatulence, however, it is rarely the cause. Yet, thorough chewing of food can go a long way toward relieving numerous digestive maladies.

Bacteria produce H2S and/or methane (both containing sulphur) when they encounter sugars, starch, and cellulose that have not been digested during passage through your small intestine.

Sorbitol, fructose, and lactose are common sugars that are poorly digested and poorly absorbed.

Sorbitol is a sweetener commonly used in low calorie foods. Fructose is used to sweeten all types of sauces, candies, and drinks – it is found almost everywhere. These sugars have been implicated in a variety of other maladies, so they should be consumed only occasionally, if at all.

Lactose is the sugar in milk. Absence (often a genetic trait) of an enzyme called lactase in the intestinal lining causes digestive trouble. Lactase breaks down lactose so that it can be absorbed through the intestine walls into the blood stream. Enzymes similar to intestinal lactase are added to milk products to break down lactose prior to consumption so it can be absorbed normally. The protein, casein, is a more common factor in milk allergy, causing similar symptoms.

Some people find that switching to yogurt, in which lactose has been broken down partially by bacteria, produces less gas than milk. Goat’s milk is more digestible than cow’s milk and is often tolerated better by people allergic to cow’s milk.

Starches are polysaccharides produced by plants. They are composed of long chains of sugars. Common sources of significant amounts of starch include wheat, oats, potatoes, corn, and rice. Rice is the most easily digested starch. Little undigested rice starch reaches your colon and the colonic bacteria. Therefore, eating rice produces little gas. Starches in wheat, oats, potatoes, and, to a lesser extent, corn, may reach the colon and the bacteria in substantial amounts. These starches can result in the production of appreciable amounts of gas.

The first line of defense against this accumulation of gas is chewing. Forty percent of starch digestion happens when your food is thoroughly mixed with saliva. Receptors in your mouth cue key enzymes to be ready to complete the digestion of these starches in your small intestine. Pancreatic enzymes, when not overwhelmed by poorly masticated foodstuff, break down sugars and starches so that they can be used as energy by your body.

Certain fruits and vegetables contain harder to digest starches that reach the colon and result in the formation of gas. These include beans, dried beans, cabbage, Brussels sprouts, onions, carrots, bananas, and dried fruits. Reducing the intake of these vegetables and fruits, as well as foods made from whole grains, may reduce gas and flatulence. However, the list of gas-producing foods is rather long, and it may be difficult to eliminate them all without severely restricting your diet. Additionally, many of these foods offer significant health benefits.

As above, chewing each bite a couple of dozen times can make a big difference.

Pre-soaking beans and slow cooking with digestion enhancing herbs (e.g., cumin, ginger, coriander) can make a difference.

Supplemental enzymes may be helpful in the short run as well. One such treatment for excessive gas is alpha-D-galactosidase, an enzyme produced by a mold. This enzyme is able to break down some of the difficult-to-digest starches in vegetables so that they may be absorbed. This prevents them from reaching the colonic bacteria and causing unnecessary production of gas. Available as Beano, it is consumed as either a liquid or tablet with meals. Beano has been shown to be effective in decreasing the incidence of intestinal gas.

Often, continuing to eat ‘offending’ foods frequently (in smaller quantities) will acclimate the body to them, allowing it to produce the proper enzymes for their digestion. It is particularly important to eat raw, fresh fruits and vegetables to replenish these enzymes.

Most vegetables and fruits contain cellulose, another type of polysaccharide that is not digested at all as it passes through the small intestine. However, unlike sugars and other starches, cellulose is used only very slowly by colonic bacteria. Therefore, the production of gas after the consumption of fruits and vegetables usually is not great unless the fruits and vegetables also contain sugars or polysaccharides other than cellulose.

We know cellulose better as fiber. Fiber slows the digestion of sugars and starches, allowing more even blood sugar. Further, fiber absorbs certain toxins in your intestines. It pushes out debris from your intestines, leading to more regular cleaning of potential trouble makers from your system. The whole mess is then evacuated with the feces. Clearing your digestive system daily like this also leads to relief from the embarrassment of flatulence.

Under normal conditions, bacteria that produce gas are limited to the colon. In some medical conditions, however, these bacteria spread backward into the small intestine. When this bacterial spread occurs, food reaches the bacteria before it can be fully digested and absorbed by the small intestine. The foreign bacteria in the small intestine have a lot of undigested food from which to form gas.

Fermented foods (e.g., miso, sauerkraut, yogurt, kimchi) are enzyme rich foods, alive with micro-organisms. Fermentation allows bacteria, yeasts and molds to "predigest" or break down carbohydrates, fats, and proteins to create "Probiotics." These friendly bacteria keep your immune system strong and support overall digestive health. They:

● aid in digestion.
● promote healthy flora in your digestive tract.
● produce beneficial enzymes.
● offer you better nutrition.
● allow your body to absorb vitamins (in particular C, and B12), minerals, nutritional value and omega 3s more effectively from foods.
● regulate the level of acidity in the digestive tract
● act as anti-oxidants.
● contain the same isothiocyanates found in cruciferous vegetables and therefore fight and prevent cancer.

Flatulence causes an annoying and embarrassing situation. The gas itself is useful in the circulatory system, as long as it gets there and can be used properly. Taking steps to prevent flatulence can also improve your overall health, including your blood pressure.


No comments: