What Is H. Pylori?

You may have heard the expression “Knowledge is power.” Well – today – we’re going to give you more power to control your diet and lifestyle – by giving you the facts. Welcome to the NutritionFacts Podcast. I’m your host – Dr. Michael Greger.

Today, we get the lowdown on a bacteria most people have never heard of. It’s called Helicobacter Pylori – or H. Pylori – for short. And, it can cause big problems – in your stomach.

For decades, Japan has had the longest life expectancy in the world, while spending just a fraction on healthcare compared to other high-income countries. This longevity has been attributed in part to Japanese dietary patterns, which are thought to have contributed to their comparatively low rates of coronary artery disease. Japan has historically had among the lowest rates of colon cancer, breast cancer, ovarian cancer, prostate cancer, bladder and blood cancers. Japan, however, has among the highest rates of stomach cancer. Yes, Japanese men may have had seven times less prostate cancer than Americans but got six times more stomach cancer. Is there some Achilles’ heel in the Japanese diet?
One of the first theories, proposed in the 1970s, was that it was the talc used to polish white rice to give it a glossy sheen. That was the case with ovarian cancer, which led to billions in damages against Johnson & Johnson’s baby powder, but that did not appear to be the case with stomach cancer. Is it just genetics? No. Studies on Japanese migrants show that as they and their children Westernize their diets and lifestyles, their stomach cancer rates drop accordingly.
Well, the most well-established risk factor for stomach cancer is H. pylori, a bacteria that infects the lining of the stomach and causes the chronic inflammation that can lead to cancer. H. pylori infection is considered a Group 1 carcinogen, indicating our highest level of certainty that it indeed causes cancer. Korea and Japan have the highest rates of stomach cancer, and among the highest incidence of H. pylori infection. Case closed, then, right? The mystery seemed to have been solved.
But then came the “African enigma.” Countries such as Nigeria had even more H. pylori, but only a fraction of Japan’s stomach cancer rates. Then came the “Indian enigma.” H. pylori is twice as prevalent in India than Japan, yet Indians get ten times less stomach cancer. Obviously, H. pylori alone can’t explain Japan’s epidemic.
Though most cases of stomach cancer are thought to be caused by H. pylori, most people with H. pylori don’t get cancer. H. pylori is one of the most common human infections. It has been estimated that half of the world’s adult population is infected with H. pylori, yet half of us don’t get stomach cancer. There must be some kind of co-factor in countries like Korea and Japan that explains their elevated cancer rates. The inflammation caused by H. pylori may just set the stage for cancer formation, increasing the susceptibility of the stomach lining to dietary carcinogens. But what’s so carcinogenic about Korean and Japanese diets?
Studies that have compared the dietary components of different Asian populations with similar H. pylori rates, but dramatically different stomach cancer rates, have suggested preserved, salted foods—both fish and vegetables—as the culprits. Fresh vegetables and fruits, on the other hand, were associated with an 85 percent reduction in stomach cancer odds, whereas consumption of fresh fish doesn’t appear associated with stomach cancer either way.
A review of sixty studies found that the consumption of pickled foods was associated with significantly higher rates of stomach cancer, though more so in Korea than Japan, perhaps because per-capita Korean consumption of salt-fermented vegetables, like kimchi, is five to eight times greater. You can’t know for sure though, until you put it to the test.
Pickled vegetable extracts can cause DNA damage in cells in a petri dish, but what about in people? Researchers in Vancouver fed people 30 ounces of fukujinzuke (assorted vegetables pickled in soy sauce) or pickled cucumbers over a three-day period. Biopsies taken from their stomach lining before the experiment started were normal, as were the biopsies taken after eating fresh carrots or cucumbers. But after just a few days of consuming pickled vegetables, moderate to severe tissue abnormalities were found, suggestive of stomach irritation.
The consumption of non-fermented soy foods, such as tofu, edamame, and soymilk, is linked to a lower risk of stomach cancer in Japan, whereas no association was found with fermented soy foods—even highly salted miso. The protection afforded by soy foods was attributed to the anti-inflammatory and anti-oxidant effects of the isoflavone compounds in soybeans.
Salt itself isn’t considered a direct carcinogen, but it may damage the stomach lining, thin the protective mucus layer, enhance H. pylori colonization, enhance the penetration of carcinogens, and enhance the formation of carcinogens. Even moderately high salt intake is associated with significantly increased risk of stomach cancer, though in Japan this effect may be limited to those already suffering from H. pylori-induced inflammation.
H. pylori is typically treated with a cocktail of multiple antibiotics. Is there any way to eradicate it naturally through diet? We’ll find out next.
In our next story, we look at what food can eradicate H. pylori in the majority of patients.

The salting and pickling of fish produces a novel DNA mutating chemical called CMBA, which is formed from a reaction of the salt, nitrite preservatives, and methionine, an amino acid found concentrated in animal protein. The nitrites can also interact with other protein components to form N-nitroso compounds, a powerful class of carcinogens found in cigarette smoke. This may explain why processed meats, such as bacon, ham, hot dogs, lunch meat, and sausage, have been tied to increased stomach cancer risk––but this extends to fresh, unprocessed, unsalted meat as well.
But wait – I thought most stomach cancer was caused by an infection with a stomach bacteria called H. pylori. There’s a synergistic interaction between H. pylori-induced inflammation gastritis and diet in the formation of stomach cancer. Check it out. Researchers in China discovered that even genetically vulnerable individuals infected with a particularly pathogenic strain of H. pylori did not appear to be at increased risk of stomach cancer, unless they ate about an ounce or more of pork per day. (An average pork chop is like about six ounces.) This is a striking example of how our diet can sometimes trump both our genes and environmental influences like cancer-causing infections. But is there a way to wipe out the H. pylori in the first place?
Normally, you’d use a triple antibiotic cocktail of drugs to kill off H. pylori, but patient compliance is difficult to maintain due to the quantity of drugs taken and the adverse side-effects. Is there anything we can eat to wipe them out instead?
Decades before its detoxifying and anti-cancer abilities were discovered, sulforaphane, that remarkable compound in cruciferous vegetables, was originally described for its antimicrobial activity. After hearing anecdotal reports of individuals with H. pylori-induced peptic ulcer disease experiencing dramatic and sometimes unexpected relief after eating three-day-old broccoli sprouts, researchers at Johns Hopkins University and elsewhere decided to put broccoli sprouts to the test. Not only did broccoli sprout extracts kill antibiotic-resistant strains of H. pylori in a petri dish, some patients who were given as little as a third of a cup of broccoli sprouts a day for a week were able to eradicate their H. pylori infection. So, how about a randomized controlled trial (broccoli sprouts vs. alfalfa sprouts) and…those given two to three servings of broccoli a day worth of sprouts were able to significantly cut down on markers of both H. pylori colonization and stomach lining inflammation.
Though broccoli sprouts may be able to eradicate H. pylori in the majority of patients—56 percent—the standard triple drug antibiotic therapy is much more effective—about 90 percent eradication. Still, for those who don’t meet the criteria for drug treatment, cruciferous vegetables may present a safe, natural way to combat H. pylori and the development of stomach cancer. A compilation of twenty-two population studies found that eating more cruciferous vegetables was associated with a significantly lower stomach cancer risk, but broccoli has never been directly put to the test, but garlic has.
Observational studies dating back to the 1960s on Japanese migrants have suggested that allium family vegetables, garlic and onion family vegetables, may be protective against stomach cancer. To date, there have been dozens of such studies published, and overall, eating lots of allium vegetables was indeed associated with significantly lower stomach cancer risk. There is evidence of publication bias, though, meaning there appears to have been other studies that failed to show such an effect, but were shelved and never published. Even if this weren’t the case, observational studies never prove cause and effect.
Maybe low garlic and onion consumption didn’t contribute to stomach cancer, for example, but rather stomach cancer contributed to low garlic and onion consumption. Decades of H. pylori stomach inflammation leading up to the cancer may have led to individuals choosing bland diets to avoid discomfort. You can’t know if garlic really helps until you put it to the test.
Louis Pasteur was evidently the first to describe the antibacterial effect of onion and garlic juices.
Petri dish studies have shown that garlic is effective in suppressing the growth of H. pylori at concentrations achievable in the stomach with a single clove. Even some antibiotic-resistant strains are susceptible. But does this translate into stopping the growth of cancer? A randomized, double-blind, controlled trial was launched to find out.
Thousands of individuals at high risk for stomach cancer from thirteen villages in China were randomized into various combinations of antibiotics, garlic supplements, and antioxidant supplements. And just a few weeks of antibiotics led to a significant decrease in subsequent precancerous stomach growths seven years later, and a significant decrease in subsequent stomach cancer by 15 years. What about the garlic? No benefit by seven years, and only a non-statistically significant reduction after 15 years. But in 2019, we got the 22-year update––15 years after the study ended. And those who had taken the garlic did indeed have a significantly lower risk of subsequently dying from cancer, though interestingly, the protective effect of garlic only seemed to manifest among nondrinkers.

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