Fiber
Written by Jerry Lau and Tommy Li
You are sitting in the toilet and it has been 10 minutes since your last attempt to finish the job. Why is it so hard to empty your rectum? You are asking yourself and regret not having a rich fiber based diet. Why is fiber so important for your health? Fibers downward regulation of cholesterol, triglycerides and glucose intestinal absorption and their blood levels, with lower postprandial insulin levels, with promoting defecation, with slowing digestion, and with a feeling of fullness, thus promoting satiety and helping to curb overeating. The fiber found in fruits and legumes stimulates the growth of colonic flora which, in turn, increases the stool weight and the amount of bacteria in the stool. Having rich fiber diets encourage the growth of certain bacteria in the colon may promote a healthy intestine. Thus, you prevent or relieve hemorrhoids and decrease symptoms of irritable bowel syndrome.
There are two different types of fibers: soluble and insoluble. Most foods contain both of these fiber types but the ratio within the food varies. The soluble fibers dissolve in water and attract with each other to form a viscous gel. On the other hand, insoluble fibers do not dissolve in water. Sources of these fibers include legumes, like beans and lentils; grains, like oats and barley; fruits; seeds, like flaxseed and psyllium; vegetables, like cabbage and cucumber. Fibers include pectin, inulin, gums, dextrins and resistant starches.
Moreover, new evidence based experiments on mice suggest that fiber may be of benefit in decreasing inflammation, pain and tissue damage associated with gout (most likely by promoting the death of neutrophils). Mice placed on a high fiber diet did not show an inflammatory response to an injection of monosodium urate (MSU) crystals into the knees. In addition to the death of neutrophils, fiber may promote the removal of the dying and dead cell debris from the affected joints.
But what essentially is fiber and its function? A fiber is a type of carbohydrate which the body can not digest on its own. Fiber passes through the body and helps regulate the body’s use of sugar, keeping hunger at bay. Fiber also plays an essential role in digestion. Without enough fiber, the body can not produce the healthy stool needed for the body to pass. It is recommended that children and adults get at least twenty to thirty grams of fiber per day for good health; in this regard, Americans need more fiber PSAs as studies have found that the average American gets only about fifteen grams instead (2). Some easy ways to increase your fiber intake include switching from fruit juices to whole fruits, replacing white rice with brown rice, eating cereals with whole grains, etc.
There are a whole host of benefits to increasing your fiber intake. These benefits range from reduced risk of heart disease and constipation to reduced risk of type 2 diabetes and breast cancer. As pharmacy students we need to be able to educate patients on the benefits of fiber and encourage them to look at nutrition and diet from a perspective of health and not solely on taste.
References:
Partula V, Deschasaux M, Druesne-Pecollo N. Associations between consumption of dietary fibers and the risk of cardiovascular diseases, cancers, type 2 diabetes, and mortality in the prospective NutriNet-Santé cohort. Am J Clin Nutr. 2020 Jul 1;112(1):195-207.
https://pubmed-ncbi-nlm-nih-gov.jerome.stjohns.edu/32369545/.
“Fiber”. The Nutrition Source. Harvard T.H. Chan. https://www.hsph.harvard.edu/nutritionsource/carbohydrates/fiber/. Accessed 2021 September 15.
Food and Nutrition
The skin and the gut are each hosts to a wide range of microorganisms. The guts microbiome provides protection to the host, aids in metabolism, and helps develop the immune system. The gut microbes defend the body against pathogens that may enter the body. The term symbiosis can be used to describe the gut as there is a balance of commensal bacteria between the gut and the body. Moreover, the gut microbiome helps to protect the body, whereas any change in this balance can increase vulnerability of the host. There is a distinct connection between the gut microbiome and several dermatological conditions. The skin is the physical barrier of the body against the external environment. The skin has its own microbial defense located mainly in the stratum corneum, hair follicles, and sebaceous glands. The gut and the skin both have an abundance of immune cells to protect the host from the commensals. The gut has a layer of epithelial cells, mucus, T cells, IgA, and dendritic cells that protect from the entrance of commensal bacteria into gut-associated lymphoid tissues (GALTS). Gut-skin axis describes how the gut interacts with the skin by engaging with the immune system to manage inflammation. The prevention of gut bacteria entering the bloodstream by the intestinal barrier maintains the health of the skin. Dermatologists Stokes and Pillsbury suggested that the gut and the skin communicate with the brain (Mahmud, M.et al.). The gut produces GABA, acetylcholine, dopamine, and serotonin that can affect skin through the nervous system. An experiment that was conducted on mice displayed the effect of GABA in atopic dermatitis. It was determined that by increasing serum IgE and IL-4, GABA can balance T helper cells type 1 and 2 levels to diminish lesions of atopic dermatitis (Mahmud, M. et al.).
Diet and drugs also have a major role in gut health and ultimately skin health. Diets high in trans fat increase harmful microorganisms and decrease healthy microbes. Consuming refined and hydrogenated oils like sunflower, canola, and vegetable oils can lead to inflammation in the gut which will present on the skin. A diet containing complex carbohydrates like fiber increases the production of SCFAs like propionate which can positively affect skin microbes. The Propionibacterium genus ferments dietary fiber and forms propionic acid which is an antibacterial that can kill community acquired MRSA strains (Mahmud, M. et al.). Antibiotics are used to eliminate infectious pathogens that are not wanted in the body. After a round of antibiotics, people can experience dysbiosis which can lead to skin problems. Prebiotics are used to promote the growth of beneficial microorganisms in the gut. Galactooligosaccharides are prebiotics that have been shown to reduce trans-epidermal water loss, erythema, atopic dermatitis, and eczema. Probiotics prevent colonization by dangerous pathogens and confer anti-inflammatory properties.
Furthermore, many vitamins and supplements can have effects on skin function. For example, vitamin A, a fat-soluble vitamin can be derived from animal sources as retinyl ester or from plants as provitamin A (Beta-carotene) which is then converted to vitamin A in the skin. Retinoids play a role in protein production, cell metabolism, cell division, affecting the thickness and color or skin, limit sebum production, and regulate the function of the sebaceous glands. Vitamin C is not produced in the body and must be supplied in the diet. It promotes collagen synthesis, protection against skin oxidation, helps with skin aging, and is involved in signaling pathways of cell growth and differentiation. Like vitamin C, vitamin E must be supplied to the body through diet. It has effects by protecting the skin from oxidative stress, improving hyperpigmentation, antiaging, and increased elasticity. Studies have shown that oral vitamin E supplementation can have a role in improvement of atopic dermatitis. Minerals are also important for the skin especially, selenium, zinc, copper, and silicon. Selenium is a strong antioxidant and protects the skin against UV radiation. Zinc is also an antioxidant and has a role in production of new cells, as well as apoptosis, and stabilization of skin cell membranes. Zinc can also affect the immune function of the skin and can be found in topical preparations like calamine as a soothing agent. Copper also protects the skin from free radicals, synthesis of collagen, and plays a role in the regeneration of skin tissue. Silicon promotes the synthesis of elastin, preserves blood vessel elasticity, and increases resistance and thickness of nail and hair fibers (Michalak, M. et al.). Omega-3 and omega-6 are useful in skin to improve hydration, regenerate a damaged skin barrier, and regulate skin metabolism. Polyphenols are compounds that can be found in plants and have smoothing, hydrating, softening, and soothing effects as well as antioxidant effects. They can be found in peppermint, oregano, berries, seeds, and vegetables. Carotenoids can be found in plants and prevent aging, stimulate collagen and elastin production, and have anti-inflammatory effects.
Dysbiosis in the gut can lead to psoriasis, atopic dermatitis, and acne. One study showed that patients with psoriasis had gut microorganisms in their plasma samples. Patients with Crohn’s disease also commonly have psoriasis as a comorbidity (Mahmud, M. et al.). This demonstrates a direct link between the gut and the skin. Psoriasis is an autoimmune skin condition where immune cells attack skin cells. Patients with psoriasis have decreased numbers of microbes, such as Bacteroides, that impair the function of the gut barrier and affect the immune system. Diet changes may have a role in improving the quality of life of patients with psoriasis. Limiting the intake of saturated fatty acids and introducing vitamin A, C, E, carotenoids, flavonoids, and selenium is important for improvement. Furthermore, metabolic syndrome and obesity are observed more frequently in patients with psoriasis indicating a link between the gut and skin. A low energy diet may be best in patients with psoriasis. Atopic dermatitis is caused by an imbalance of Th1 and Th2. A leaky gut due to diet may be responsible for allowing toxins, food residues and pathogens to enter the blood and induce Th2 immune responses. Studies have shown that a decrease in many gut microorganisms and an increase of Proteobacteria may be a cause of acne. The mTOR pathway is another mechanism for acne that is activated by high glycemic load. A high fat diet on its own also can lead to the development of acne due to a lower release rate of AMPs in the small intestine leading to dysbiosis.
Maintaining a healthy gut is important for many processes in the body, including skin health. There is a clear link between the skin and the gut. Further research is needed for the use of prebiotics, probiotics, and supplements in gut health and as treatment of skin conditions.
Resources
Garbicz, J., Całyniuk, B., Górski, M., Buczkowska, M., Piecuch, M., Kulik, A., & Rozentryt, P. (2021). Nutritional Therapy in Persons Suffering from Psoriasis. Nutrients, 14(1), 119. https://doi.org/10.3390/nu14010119
Mahmud, M. R., Akter, S., Tamanna, S. K., Mazumder, L., Esti, I. Z., Banerjee, S., Akter, S., Hasan, M. R., Acharjee, M., Hossain, M. S., & Pirttilä, A. M. (2022). Impact of gut microbiome on skin health: gut-skin axis observed through the lenses of therapeutics and skin diseases. Gut microbes, 14(1), 2096995. https://doi.org/10.1080/19490976.2022.2096995
Michalak, M., Pierzak, M., Kręcisz, B., & Suliga, E. (2021). Bioactive Compounds for Skin Health: A Review. Nutrients, 13(1), 203. https://doi.org/10.3390/nu13010203