Increasing fiber in your diet may increase gas
Q: My husband and I recently got our family onto a healthier diet - no processed foods and lots more vegetables, beans and legumes. It's not easy, and we're struggling to stay on track. On top of that, we all have gas. Why does that happen? What can we do?
A: You're far from alone in finding it a challenge to make long-term improvements to your diet. For proof, we need look no further than the numerous meal delivery services that have popped up in recent years, each one promising easy access to balanced and healthful food. There's also the fact that the aromas, flavors and textures of our favorite foods are as much about comfort and familiarity as they are about satiety.
People who switch to new diets often wind up feeling both overwhelmed and deprived. And when you add in the discomfort and occasional embarrassment of intestinal gas, even the best intentions can waver. When you made the change from eating processed foods to more fresh and whole foods, you introduced a lot of fiber into your diet. Plant-based foods contain both soluble and insoluble fiber. It's the latter that give some of us problems.
Soluble fiber dissolves in water and can be absorbed by the body. But the insoluble fiber found in whole grains, legumes, beans, and vegetables like broccoli, cabbage, asparagus and cauliflower passes through the stomach undigested and moves on to the large intestine. There, the insoluble fiber becomes food for the trillions of microorganisms that populate the gut. They digest it for us via fermentation, the byproduct of which is the gas you and your family have been experiencing.
Beans also contain raffinose, which is one of a group of complex sugars known as oligosaccharides. We humans can't digest these sugars, but the bacteria in the gut can. And again, gas is the byproduct of that digestion.
There are several steps you can take to help ease the gas situation. When fiber has been absent from a diet, it's a good idea to introduce it gradually. You want to give the microflora in your gut time to get used to the new influx of food. An analysis of three studies that looked into the question of beans and gas found that the participants' bodies gradually adjusted. Within three to four weeks of adding beans to their diet, they had returned to normal levels of gas production. There is also some evidence that soaking dry beans at least 12 hours before cooking can reduce the level of raffinose that leads to gas.
As you increase your fiber intake, it's also important to be sure you're staying adequately hydrated. Fiber absorbs a lot of water as it goes through the digestive process. When you don't drink enough water in a high-fiber diet, you risk developing constipation. The increase in gas production that accompanies the switch to a diet of whole foods can be disconcerting. However, research suggests that it's actually an encouraging sign of the health and activity of your gut microbiome.
Sodas and hydration: In response to a column about dehydration in older adults, a reader had a question about diet soda. "You said diet sodas weren't a good choice for staying hydrated, but you didn't say why," she wrote. "I drink one diet cola per day, on average. Why would that affect hydration, because I also drink coffee, herbal teas and water?" The caution about diet sodas is based on the growing body of evidence that links them to certain adverse health effects. These include poor blood sugar control, increased risk of heart disease and disruption of the gut microbiome. With that in mind, even casual drinkers might consider cutting back or switching to fizzy water instead.
Wondering about water: A reader from Virginia Beach, Virginia, also had a hydration question. "We regularly read that we should drink at least eight glasses of water a day. Do other drinks count toward that total if they contain water, like soft drinks, iced tea, coffee and fruit juices?" The answer is yes, all beverages add to your daily fluid intake. It's important to remain aware of the sugar in soft drinks and fruit juices, and sweeteners you may add to coffee and tea. While the "eight glasses" rule is easy to remember, individual needs do vary. Urine that is pale yellow or colorless is a good sign you're adequately hydrated.
Food for thought: We heard from a reader in California who asked for clarity regarding the advice to take medication with food. "Although you explained why we must take some meds with food, you never explained how," he wrote. "Do we take meds halfway through the meal, after the meal, before eating?" It's a great question, and the answer depends on the medication involved. In the majority of cases, the idea is to eat something immediately before you take the medication. That's so you're not taking meds on an empty stomach. Food aids in absorption and helps prevent stomach irritation. However, liquid preparations, such as those used to treat oral thrush or mouth ulcers, should be used after eating or drinking. That's so they don't get washed away. It's also important to be aware of potential food-drug interactions. This includes calcium-rich foods and many antibiotics; pickled, cured and fermented foods when taking certain antidepressants; and grapefruit and its juice and statins. This is by no means a complete list. Whenever you get a prescription filled, it's a good idea to ask the pharmacist for specific instructions on how to take the medication, and for information about potential interactions with foods, supplements and other medications.
Thank you, as always, for taking the time to write to us. We love hearing from you. Remember to keep up your coronavirus precautions, and please, if you haven't yet, do get the vaccine.
• Dr. Eve Glazier is an internist and associate professor of medicine at UCLA Health. Dr. Elizabeth Ko is an internist and assistant professor of medicine at UCLA Health. Send your questions to askthedoctors@mednet.ucla.edu.