Special carbohydrate diet (SCD) is a restrictive diet, which removes many common carbohydrate sources, including all grains, dairy products, most starches and many types of sugar, to help heal the digestive system. According to the founder of SCD diet, at least 75% people who strictly follow this diet have significantly improved their health according to the feedback in the past decades. See (website to break the vicious circle)
Although SCD lifestyle may restrict people's life and require people to eat less "Western-style diet" food, it can bring obvious benefits to people with impaired digestive system, including inflammatory bowel disease, Crohn's disease, ulcerative colitis, irritable bowel syndrome and SIBO.
Even if you don't have a diagnosable digestive system disease, but you have persistent symptoms such as constipation or flatulence, you can also alleviate the symptoms by choosing the type of carbohydrates contained in your diet. Why do we have to do that？ Removing the most difficult carbohydrates and keeping only certain foods (such as vegetables) that are most easily digested and metabolized in the diet will help reduce bacterial fermentation, gas accumulation and intestinal permeability in the intestine.
SCD diet is not only aimed at the potential problems in gastrointestinal tract, but also at the symptoms related to bacterial overgrowth, inflammation and blocked nutrient absorption. By removing "complex carbohydrates" from the diet, including lactose, sucrose (sugar) and many synthetic ingredients, we can improve the digestion process, reduce toxins, and improve overall health as inflammation subsides.
In addition, it is also very useful for anyone who is sensitive to food and intolerant to food such as FODMAP, because it can cause constipation, diarrhea, bloating, flatulence, fatigue and other problems. People who take drugs that interfere with the digestion of certain carbohydrates can also get relief. It has even been suggested that SCD diet can help learning disabilities, such as autism.
Who proposed and promoted SCD diet? Dr Elaine Gottschall, a biochemist, wrote a book "Breaking the vicious circle: achieving intestinal health through diet", which describes her effective treatment plan now, that is, following SCD diet to reduce the inflammatory reaction caused by gastrointestinal tract.
In his book Breaking the Vicious Cycle, Gottshall explained how the problems in the digestive system lead to intestinal permeability (usually called "intestinal leakage"), which makes the particles in the intestine pass through the intestinal intima and enter the blood, thus triggering a series of adverse reactions. Immune system.
You may have heard of the gap diet plan and scheme (created by Dr. Natasha Campbell), which aims to remove certain types of carbohydrates, which are known to aggravate intestinal permeability and inflammation.
SCD diet and gap diet have a lot in common. The food elimination during the gap diet is carried out in stages. The food list of gap diet includes many foods that use SCD diet, such as most vegetables, fish, healthy oils, grass carnivores, sprouted nuts, seeds and beans.
It has been proved that SCD diet is helpful to treat difficult diseases, such as Crohn's disease and ulcerative colitis. Crohn's disease is a chronic intestinal inflammation with unknown causes, but a published study shows that the change of diet structure plays an important role. Eliminating specific complex carbohydrates can usually be very successful in relieving the symptoms of many patients. For details, please refer to (Nutritional treatment of Crohn's disease in children: special carbohydrate diet).
A study involving children with Crohn's disease found that children who used SCD diet 12 weeks and 52 weeks had obvious improvement in clinical and mucosal aspects (see the clinical and mucosal improvement of Crohn's disease-specific carbohydrate diet for details). Another study found that after three to six months, SCD diet is very beneficial to patients with ulcerative colitis, thus improving clinical symptoms and making some patients completely relieved. (See Special Carbohydrate Diet for Relieving Severe Ulcerative Colitis)
In addition, a study conducted by the Pediatrics Department of Seattle Children's Hospital and Washington University on 20 16 found that SCD diet provided hope for patients with inflammatory bowel disease who could not be relieved by conventional treatment alone. They found that a comprehensive diet plan combined with special carbohydrate diet and adjuvant therapy was helpful to improve the clinical and laboratory data of patients with Crohn's disease and ulcerative colitis. (See IBD Academic Center's Special Carbohydrate Diet for Children with Inflammatory Bowel Disease in Clinical Practice for details. )
Excessive entry of bacteria into the small intestine will lead to an increase in gases and toxins produced by fermentation. This may lead to the accumulation of toxic waste, discomfort, difficulty in digesting food, and even inability to absorb nutrients correctly. Symptoms vary from person to person, but may include constipation, abdominal distension, abdominal distension, diarrhea and loss of appetite.
Diarrhea is a common symptom of digestive system diseases, because undigested carbohydrates and carbohydrates remaining in the intestine will promote the absorption of water and nutrients into the colon, thus accelerating the removal of waste and liquids. Inflammation is also a factor leading to diarrhea and other symptoms. (See diarrhea mechanism of inflammatory bowel disease for details)
The harmful by-products produced in the fermentation process will affect the enzymes produced in the digestive tract, which are necessary for food metabolism and nutrient absorption. Important digestive enzymes located on the surface of small intestine will be damaged or reduced due to the growth of bacteria and their toxic wastes, thus hindering the absorption of normal vitamins and minerals. The mucosal layer of the small intestine is also adversely affected by toxic by-products, so it begins to produce more protective mucus coatings, which further inhibits the normal digestion process. (See the principle of digestive system for details)
Patients, especially children with intestinal diseases, insufficient risk, weight loss and diarrhea, may be harmful. A study published in the World Journal of Gastroenterology 20 16 found that children with inflammatory bowel disease can gain weight and height healthily while maintaining a strict SCD diet to improve their overall symptoms. (For details, see the response of strict specific carbohydrate diet to Crohn's disease in children. )
The important part of gastrointestinal mucosa is tiny microvilli, which forms a natural barrier of the intestine and separates the inside and outside of the intestine (blood).
The longer the absorption of nutrients is inhibited (such as folic acid and vitamin B 12, which are helpful to the establishment of mucosal layer), the more times of fermentation, the more serious the damage of microvilli and intestinal barrier. This will lead to intestinal leakage, and tiny particles will enter the wrong place in the blood, thus sending a signal to the immune system that something is wrong. Studies have shown that systemic inflammation can be better controlled by reversing this process. (See Anti-inflammatory Diet for Inflammatory Bowel Disease: A Case Report)
Besides the gastrointestinal tract, the brain is also affected by inflammation and bacterial fermentation. Gastrointestinal dysfunction is very common in patients with autism spectrum disorder (ASD), and the role of microbial community in ASD is still under study. There is evidence that the intestinal flora of autistic patients has changed, which may affect the intestinal-brain interaction by changing the normal cognitive development. (For details, see Intestinal Bacteria in Children with Autism Spectrum Disorder: Challenges and Hope of Studying How Complex Environment Affects Complex Diseases.). )
There is evidence that lactic acid produced during the fermentation of intestinal bacteria will affect brain function and behavior.
For those unfamiliar with SCD diet or similar eating habits (such as gap diet), this diet seems difficult and restrictive at first. SCD diet excludes many common grains, dairy products and packaged foods, not to mention adding sugar, many starches and many types of drinks.
According to its chemical composition analysis, food is forbidden or allowed to eat. Specifically, carbohydrates are allowed to be classified as monosaccharides with single molecular structure, but complex carbohydrates called disaccharides and polysaccharides are not allowed.
The reason is the way complex carbohydrates are broken down in the digestive tract. They usually feed harmful bacteria in the intestine and lead to increased fermentation, because they are difficult for many people to digest completely. Disaccharides (disaccharides) include lactose, sucrose, maltose and isomaltooligosaccharides, and polysaccharides include grains, starch and starchy vegetables.
As the website "Breaking the vicious circle" said: "The simpler the structure of carbohydrates, the easier it is for the human body to digest and absorb. Monosaccharide (single molecule of glucose, fructose or galactose) can be absorbed by human body without being decomposed by digestive enzymes. These are trustworthy sugars in our diet. " (See Dietetic Science for details)
Once complex carbohydrates and harmful additives are removed from the diet, the bacterial balance in the intestine will be improved. Another advantage is that people who eat SCD diet can concentrate more on getting calories from nutritious foods. Specific carbohydrate diet has a lot in common with ancient diet. People have been eating unprocessed food for hundreds of thousands of years.
SCD diet mainly includes high-quality herbivorous meat birds, wild fish, eggs, vegetables, soaked/germinated nuts and some low-sugar fruits and yogurt. On the other hand, it excludes "modern food" and foods that may contain additives in processed foods.
The food categories included in SCD diet include:
Foods and ingredients not allowed in SCD diet include:
You can find complete information about all "legal and illegal" SCD diet foods on the website "Breaking the vicious circle". (See SCD food list for details)
Can you try some ideas of SCD diet at home, or some useful skills that can help you in the process of practicing SCD diet lifestyle? (See what is a special carbohydrate diet for details)
The basic principle of SCD diet is that many digestive system diseases are caused by "excessive growth and imbalance of intestinal microbial flora", in other words, there are too many kinds of harmful bacteria, yeasts and fungi in the body, mainly concentrated in the intestine. The immune system is also mainly located in the intestine. In fact, the human digestive tract is considered to be an ecosystem where many kinds of bacteria coexist. Research shows that most people's microbial communities contain more than 400 different types of bacteria!
Our diet has a great influence on the balance of microorganisms in our digestive system, considering that these microorganisms actually thrive in the body by the food we eat. Therefore, if we change the type of diet, we can change the reproduction mode of harmful bacteria. Not all bacteria in the intestine are harmful. In fact, many of them are beneficial and important for immune function, hormone balance and even weight control. The purpose of SCD diet is to reduce bad species and make good species flourish, so as to make the flora develop in a balanced way.
As Dr. Gottschall said, "By changing the nutrients we eat, we can influence the composition of intestinal flora, restore its balance, heal our digestive tract and restore proper absorption."
Want to know whether carbohydrates in the diet are related to reducing the presence of certain bacteria in the intestine? Many of our "harmful bacteria" (microorganisms) can survive by getting nutrients from certain types of carbohydrates, which are not properly digested, and in the process, they will produce wastes and toxins through bacterial fermentation. Fermentation produces gases and toxins, such as lactic acid, acetic acid, methane, carbon dioxide and hydrogen. These gases and toxins will not only make you feel bloating, bloating, but also damage and stimulate the stomach, thus aggravating intestinal leakage (intestinal permeability).
The "vicious circle" referred to by Dr. Gottschall is related to how microorganisms migrate to the small intestine and stomach when they are overgrown (called SIBO, which is the acronym for "overgrowth of bacteria in the small intestine"). Microorganisms ferment in the small intestine and stomach, and then leave toxic digestive by-products, thus further causing problems. This may lead to bacterial variation, gastric acidity change, nutritional deficiency and inflammation deterioration, thus affecting the whole brain (from brain to skin). Many diet plans for treating SIBO are very similar to SCD diet.
The root cause of many digestive system diseases and symptoms is bacterial overgrowth, and the reasons for bacterial overgrowth include: (See Inflammatory Bowel Disease: Etiology and Immunobiology, Risk Environmental Factors of Inflammatory Bowel Disease for details).