Unit 12. Food and Nutrition Issues
12.3 Nutrition, Health and Disease
Disorders That Can Compromise Health
When nutrients and energy are in short supply, cells, tissues, organs, and organ systems do not function properly. Unbalanced diets can cause diseases and, conversely, certain illnesses and diseases can cause an inadequate intake and absorption of nutrients, simulating the health consequences of an unbalanced diet. Overeating high-fat foods and nutrient-poor foods can lead to obesity and exacerbate the symptoms of gastroesophageal reflux disease (GERD) and irritable bowel syndrome (IBS). Many diseases and illnesses, such as celiac disease, interfere with the body getting its nutritional requirements. A host of other conditions and illnesses, such as food allergies, cancer, stomach ulcers, Crohn’s disease, and kidney and liver disease, also can impair the process of digestion and/or negatively affect nutrient balance and decrease overall health. Some illnesses that can compromise health are chronic and persist for a long time, some are communicable and can be transmitted between people, and some are non-communicable and are not infectious.
Gastroesophageal Reflux Disease
Gastroesophageal reflux disease (GERD) is a persistent form of acid reflux that occurs more than two times per week. Acid reflux occurs when the acidic contents of the stomach leak backward into the esophagus and cause irritation. It is estimated that GERD affects 25 to 35 percent of the US population. An analysis of several studies published in the August 2005 issue of Annals of Internal Medicine concludes that GERD is much more prevalent in people who are obese.[1] The most common GERD symptom is heartburn, but people with GERD may also experience regurgitation (flow of the stomach’s acidic contents into the mouth), frequent coughing, and trouble swallowing.
There are other causative factors of GERD that may be separate from or intertwined with obesity. The sphincter that separates the stomach’s internal contents from the esophagus often does not function properly and acidic gastric contents seep upward. Sometimes the peristaltic contractions of the esophagus are also sluggish and compromise the clearance of acidic contents. In addition to having an unbalanced, high-fat diet, some people with GERD are sensitive to particular foods—chocolate, garlic, spicy foods, fried foods, and tomato-based foods—which worsen symptoms. Drinks containing alcohol or caffeine may also worsen GERD symptoms. GERD is diagnosed most often by a history of the frequency of recurring symptoms. A more proper diagnosis can be made when a doctor inserts a small device into the lower esophagus that measures the acidity of the contents during one’s daily activities. About 50 percent of people with GERD have inflamed tissues in the esophagus.
The first approach to GERD treatment is dietary and lifestyle modifications. Suggestions are to reduce weight if you are overweight or obese, avoid foods that worsen GERD symptoms, eat smaller meals, stop smoking, and remain upright for at least three hours after a meal. People with GERD may not take in the nutrients they need because of the pain and discomfort associated with eating. As a result, GERD can be caused by an unbalanced diet and its symptoms can lead to a worsening of nutrient inadequacy, a vicious cycle that further compromises health. Some evidence from scientific studies indicates that medications used to treat GERD may accentuate certain nutrient deficiencies, namely zinc and magnesium. When these treatment approaches do not work surgery is an option. The most common surgery involves reinforcing the sphincter that serves as a barrier between the stomach and esophagus.
Irritable Bowel Syndrome
Irritable bowel syndrome (IBS) is characterized by muscle spasms in the colon that result in abdominal pain, bloating, constipation, and/or diarrhea. Interestingly, IBS produces no permanent structural damage to the large intestine as often happens to patients who have Crohn’s disease or inflammatory bowel disease. It is estimated that one in five Americans displays symptoms of IBS. The disorder is more prevalent in women than men. Two primary factors that contribute to IBS are an unbalanced diet and stress.
Symptoms of IBS significantly decrease a person’s quality of life as they are present for at least twelve consecutive or nonconsecutive weeks in a year. Large meals and foods high in fat and added sugars, or those that contain wheat, rye, barley, peppermint, and chocolate intensify or bring about symptoms of IBS. Additionally, beverages containing caffeine or alcohol may worsen IBS. Stress and depression compound the severity and frequency of IBS symptoms. As with GERD, the first treatment approaches for IBS are diet and lifestyle modifications. People with IBS are often told to keep a daily food journal to help identify and eliminate foods that cause the most problems. Other recommendations are to eat slower, add more fiber to the diet, drink more water, and to exercise. There are some medications (many of which can be purchased over-the-counter) to treat IBS and the resulting diarrhea or constipation. Sometimes antidepressants and drugs to relax the colon are prescribed.
Oral Disease
Oral health refers not only to healthy teeth and gums but also to the health of all the supporting tissues in the mouth, such as ligaments, nerves, jawbone, chewing muscles, and salivary glands. Over ten years ago, the Surgeon General produced its first report dedicated to oral health, stating that oral health and health, in general, are not separate entities.[2]
Instead, oral health is an integral part of overall health and well-being. Soft drinks, sports drinks, candies, desserts, and fruit juices are the main “fermentable sugars” sources in the American diet. (Bacteria quickly metabolize fermentable sugars in a process known as fermentation. Glucose, fructose, and sucrose are three examples.) Bacteria in the mouth convert sugars and starches to acids that erode tooth enamel. The acid creates holes (cavities) in the teeth. The acid also damages the gums, leading to gingivitis (characterized by inflamed and bleeding gums). Saliva is a natural “mouthwash” that neutralizes the acids helping to prevent cavities.
According to Healthy People 2010, 23 percent of US children have cavities by the age of four, and by second grade, one-half of all children in this country have at least one cavity.[3]
Cavities are an epidemic health problem in the United States and are associated with poor diet, but other contributors include poor dental hygiene and the inaccessibility to regular oral health care. A review in Academic Pediatrics reports that “frequent consumption of fast-releasing carbohydrates, primarily in the form of dietary sugars, is significantly associated with increased dental caries risk.”[4] In regards to sugary soft drinks, the American Dental Association says that drinking sugary soft drinks increases the risk of decay formation.[5]
Colon Health
A substantial health benefit of whole grain foods is that fiber actively supports digestion and optimizes colon health. (This can be more specifically attributed to the insoluble fiber content of whole grains.) There is good evidence supporting that insoluble fiber prevents the irritating problem of constipation and the development of diverticulosis and [6] Ten to 25 percent of people who have diverticulosis go on to develop diverticulitis.[7] Symptoms include lower abdominal pain, nausea, and alternating between constipation and diarrhea.
The chances of developing diverticulosis can be reduced with fiber intake because of what the breakdown products of the fiber do for the colon. The bacterial breakdown of fiber in the large intestine releases short-chain fatty acids. These molecules have been found to nourish colonic cells, inhibit colonic inflammation, and stimulate the immune system (thereby providing protection of the colon from harmful substances). Additionally, the bacterial indigestible fiber, mostly insoluble, increases stool bulk and softness increasing transit time in the large intestine and facilitating feces elimination. One phenomenon of consuming foods high in fiber is increased gas, since the byproducts of bacterial digestion of fiber are gases.
Many studies have found a link between high dietary-fiber intake and a decreased risk for colon cancer. [8] There is some evidence that specific fiber types (such as inulin) may protect against colon cancer, but more studies are needed to conclusively determine how certain fiber types (and at what dose) inhibit colon cancer development.
Learning Activities
Technology Note: The second edition of the Human Nutrition Open Educational Resource (OER) textbook features interactive learning activities. These activities are available in the web-based textbook and not available in the downloadable versions (EPUB, Digital PDF, Print_PDF, or Open Document).
Learning activities may be used across various mobile devices, however, for the best user experience it is strongly recommended that users complete these activities using a desktop or laptop computer.
- Hampel H, Abraham NS, El-Serag HB. (2005). Meta-Analysis: Obesity and the Risk for Gastroesophageal Reflux Disease and Its Complications. Annuals of Internal Medicine, 143(3), 199–211. http://www.ncbi.nlm.nih.gov/pubmed/16061918. Accessed April 12, 2018. ↵
- Office of the Surgeon General (US). National Call To Action To Promote Oral Health. National Institute of Dental and Craniofacial Research (US). 2003; 03-5303. https://www.ncbi.nlm.nih.gov/books/NBK47472/. Accessed April 15, 2018. ↵
- Continuing MCH Education in Oral Health. Oral Health and Health Care. http://ccnmtl.columbia.edu/projects/otm/index.html. Accessed April 12, 2018. ↵
- Mobley C, Marshall T. (2009). The Contribution of Dietary Factors to Dental Caries and Disparities in Caries. Academy of Pediatrics, 9(6), 410–14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2862385/. Accessed April 15, 2018. ↵
- Foods that Affects your Teeth. American Dental Association. https://www.mouthhealthy.org/en/nutrition/food-tips. Accessed April 15, 2018. ↵
- [pb_glossary id="3715"]diverticulitis[/pb_glossary]. Diverticulosis is a benign condition characterized by outpouches of the colon. Diverticulitis occurs when the outpouches in the lining of the colon become inflamed. Interestingly, diverticulitis did not make its medical debut until the early 1900s, and in 1971 was defined as a deficiency of whole-grain fiber. According to the National Digestive Diseases Information Clearinghouse, 10 percent of Americans over the age of forty have diverticulosis, and 50 percent of people over the age of sixty have the disorder.[footnote]Diverticular Disease. National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health. http://digestive.niddk.nih.gov/ddiseases/pubs/diverticulosis/. Accessed April 15, 2018. ↵
- Diverticular Disease. National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health. http://digestive.niddk.nih.gov/ddiseases/pubs/diverticulosis/. Accessed April 15, 2018. ↵
- Ma Y, Hu M, Zhou L, Ling S, Li Y, Kong B, Huang P. Dietary fiber intake and risks of proximal and distal colon cancers: A meta-analysis. Medicine (Baltimore). 2018 Sep;97(36):e11678. doi: 10.1097/MD.0000000000011678. PMID: 30200062; PMCID: PMC6133424. ↵
Containing a high amount of vitamins, minerals, and protein compared to calories.
You should now understand the problems with consuming too much added sugar, but what if you’ve sworn off regular soda and switched to diet versions? What if you’re choosing “sugar-free” products, sweetened with sugar substitutes like aspartame, saccharin, or stevia? Are these a better choice?
Figure 4.40. Examples of products containing high-intensity sweeteners: diet soda, sugar-free chocolate, and bulk containers of Splenda and stevia extract
Diet sodas are the biggest source of sugar substitutes in the American diet, but these ingredients are found in a range of foods, including ice cream, yogurt, cereals, iced tea, energy drinks, candy, cookies, granola bars, salad dressings, frozen dinners, and energy bars.1 Products containing sugar substitutes are often labeled as sugar-free or “lite,” but some don’t have any front-of-package labeling with this information, and you may not even realize that you’re consuming them. With more consumers watching their sugar intake, the use of sugar substitutes is growing, and the food industry is working hard to market them as a healthier choice. We can expect to see them in more and more products, so it’s important to understand what these substances are and what they may mean for our health.
What Are Sugar Substitutes?
You may find sugar substitutes called lots of different things, including artificial, non-nutritive, high-intensity, or low-calorie sweeteners. Regardless of the name, these are substances that have a sweet taste but few or no calories.2 In fact, they are much sweeter than sucrose, so a tiny amount can add a lot of sweetness to food. (Sweetener packets like Splenda and Equal contain a small amount of sweetener and a lot of filler ingredients.)
Table 4.5. Sugar substitutes approved by the FDA for use in the United States with their brand names and sweetness relative to sucrose.3
Sweetener |
Brand Names |
Sweetness (relative to sucrose) |
Acesulfame Potassium (Ace-K) |
Sweet One® Sunett® |
200x |
Advantame |
|
20,000x |
Aspartame |
Nutrasweet® Equal® Sugar Twin® |
200x |
Neotame |
Newtame® |
7,000-13,000 |
Saccharin |
Sweet'N Low® Sweet and Low® Sweet Twin® Necta Sweet® |
200-700x |
Sucralose |
Splenda® |
600x |
Luo Han Guo or monk fruit extracts |
Nectresse® Monk Fruit in the Raw® PureLo® |
100-250 x |
Stevia |
Truvia® PureVia® Enliten® |
200-400 x |
Unlike regular sugar, the sweeteners listed in the table above are not associated with dental caries, and they generally don’t raise blood glucose.1
Sugar alcohols are another type of sugar substitute. They include sorbitol, mannitol, lactitol, erythritol, and xylitol. They are chemically similar to monosaccharides but different enough that they aren’t processed in the body to the same extent. However, they are at least partially metabolized and contain about 2 kcal/gram (compared with 4 kcal/gram for sucrose). (An exception is erythritol, which contains just 0.2 kcal/g.) Unlike the sweeteners listed in the table above, they are not “high-intensity” but instead are generally less sweet than sucrose. Because they are not fully digested, consuming large amounts of them can cause bloating, gas, and diarrhea.1
Sugar alcohols are often used in sugar-free chewing gums and breath mints and can carry a health claim that they don’t promote tooth decay, because mouth bacteria can’t easily metabolize them. Xylitol in particular has been studied for its ability to decrease the incidence of tooth decay. However, these studies generally use large doses. For example, a person might have to chew xylitol gum five times per day to see a benefit. The American Academy of Pediatric Dentistry supports the use of xylitol but says the evidence for benefit is not clear and that amounts required may not be practical in real life.4
Can Sugar Substitutes Help With Weight Loss?
When people choose diet soda or a sugar-free dessert, they’re probably assuming that it’s a healthier choice and perhaps that it could help them lose weight. However, studies show this isn’t necessarily the case.
In the short-term, if someone who drinks a lot of sugar-sweetened beverages switches to diet versions, studies show that this can result in weight loss. That makes sense, because you’re removing a lot of empty calories from the diet.5
However, in the long-term, studies show there isn’t a clear benefit to consuming sugar substitutes. A recent systematic review and meta-analysis combined the results of studies that lasted at least 6 months.6 Among the randomized controlled trials, they found no difference in body mass index (BMI—a measure of the ratio of body weight to height) between people who consumed sugar and those who consumed sugar substitutes. Observational studies that tracked large groups over years found that people who consumed sugar substitutes tended to have a higher BMI, greater weight and waist circumference, and a higher incidence of obesity, hypertension, metabolic syndrome, type 2 diabetes, and cardiovascular events.7 Because these are observational studies, we can’t conclude that the sugar substitutes cause these health outcomes, but we can conclude that their use is not associated with better health.
When it comes to weight management, the goal is to adopt eating habits that support a sustainable healthy body weight. Sugar substitutes might help in the short-term with decreasing calorie intake and perhaps gradually moving away from sweetened beverages, but better long-term goals for health would be to shift to water and other unsweetened beverages. If you’re looking for a way to sweeten your oatmeal or yogurt, you might try adding fresh fruit rather than sugar or an artificial sweetener packet. (Or go ahead and add a bit of brown sugar or a drizzle of honey, keeping in mind the overall goal of moderation.)
Are High-Intensity Sweeteners Safe?
Over the years, there have been a number of concerns about non-nutritive sweeteners. For example, in the 1970s, studies showed that saccharin was linked to bladder cancer in lab rats, so it was labeled as a potential carcinogen, although its use as a sweetener continued. In 2000, after many studies showed no link between cancer and saccharin, the warning labels were no longer required. Some studies have also raised concerns about a link between aspartame and sucralose and cancer, but the FDA has reviewed this evidence and concluded: “Based on the available scientific evidence, the agency has concluded that the high-intensity sweeteners approved by FDA are safe for the general population under certain conditions of use.” The National Cancer Institute also says there is no clear evidence that high intensity sweeteners cause cancer.8
Figure 4.41. A “Saccharin Notice” sign warns consumers that a grocery store shelf contains products with saccharin, which has been shown to cause cancer in laboratory animals. Between 1977 and 2000, products containing saccharin had to include a cancer warning label. This requirement was removed after the U.S. Department of Health and Human Services determined it was not a concern in humans at doses typically consumed.
There are other emerging safety concerns about sugar substitutes, though. Small studies on both mice and humans show that consuming artificial sweeteners can change our gut bacteria and cause glucose intolerance.9-11 Glucose intolerance means that blood glucose is abnormally elevated, showing that glucose metabolism is not working properly, and it is a precursor to the development of diabetes. Other researchers worry that having the taste of sweetness signaled to the brain without accompanying calories could derail our normal pathways for sensing hunger and satiety and for regulating glucose metabolism.12 This research is alarming but still preliminary. However, it is an active area of study, and we can expect more information to emerge in the years to come.
Are Natural Sweeteners Better Than Artificial Ones?
Sweeteners made from the stevia plant and from monk fruit extracts are both derived from plants and so are considered more natural than the other choices. However, it’s important to not confuse natural with safe. Remember that many things in nature are dangerous, even deadly. (Consider cyanide, poisonous mushrooms, and botulinum toxin, for example.) Stevia sweeteners, which are growing in popularity and are often marketed as a more natural alternative, are made through a highly industrial extraction process, and some are produced by genetically-modified yeast. None of that makes them inherently less safe, but it does highlight that they aren’t exactly natural.
Figure 4.42. A box of Sweetleaf sweetener, marketed as “Natural Stevia Sweetener.”
What’s important is how well these products are tested and studied for their safety. The Center for Science in the Public Interest, a consumer advocacy nonprofit organization, has criticized the FDA for not requiring more testing of stevia and monk fruit extracts, although they recommend stevia as one of the safer options for sugar substitutes based on existing data. However, recent research has shown that, like artificial sweeteners, stevia also affects the growth of gut bacteria.
What’s the Bottom Line?
Sugar substitutes can add sweetness to a food without the calories, and they aren’t associated with tooth decay. Despite concerns over the years, they probably don’t cause cancer. However, they may not help with weight loss or maintenance in the long-term, and recent research shows that they may alter the gut microbiota and metabolic health.
Review Questions:
References:
1Center for Science in the Public Interest. (2015). Sweet Nothings: Safe... Or scary? The inside scoop on sugar substitutes.
2Food and Drug Administration. (2019b). High-Intensity Sweeteners. FDA. Retrieved from http://www.fda.gov/food/food-additives-petitions/high-intensity-sweeteners
3Food and Drug Administration. (2019a). Additional Information about High-Intensity Sweeteners Permitted for Use in Food in the United States. FDA. Retrieved from http://www.fda.gov/food/food-additives-petitions/additional-information-about-high-intensity-sweeteners-permitted-use-food-united-states
4American Academy of Pediatric Dentistry. (2015). Policy on the Use of Xylitol. Retrieved from https://www.aapd.org/research/oral-health-policies--recommendations/use-of-xylitol/#section-policy-statement
5de Ruyter, J. C., Olthof, M. R., Seidell, J. C., & Katan, M. B. (2012). A Trial of Sugar-free or Sugar-Sweetened Beverages and Body Weight in Children. New England Journal of Medicine, 367(15), 1397–1406. https://doi.org/10.1056/NEJMoa1203034
6Azad, M. B., Abou-Setta, A. M., Chauhan, B. F., Rabbani, R., Lys, J., Copstein, L., … Zarychanski, R. (2017). Nonnutritive sweeteners and cardiometabolic health: A systematic review and meta-analysis of randomized controlled trials and prospective cohort studies. CMAJ, 189(28), E929–E939. https://doi.org/10.1503/cmaj.161390
7Pearlman, M., Obert, J., & Casey, L. (2017). The Association Between Artificial Sweeteners and Obesity. Current Gastroenterology Reports, 19(12), 64. https://doi.org/10.1007/s11894-017-0602-9
8National Cancer Institute. (2005, August 18). Artificial Sweeteners and Cancer. Retrieved September 20, 2018, from https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/artificial-sweeteners-fact-sheet
9Shell, E. R. (n.d.). Artificial Sweeteners May Change Our Gut Bacteria in Dangerous Ways. https://doi.org/10.1038/scientificamerican0415-32
10Suez, J., Korem, T., Zeevi, D., Zilberman-Schapira, G., Thaiss, C. A., Maza, O., … Elinav, E. (2014). Artificial sweeteners induce glucose intolerance by altering the gut microbiota. Nature, 514(7521), 181–186. https://doi.org/10.1038/nature13793
11Wang, Q.-P., Browman, D., Herzog, H., & Neely, G. G. (2018). Non-nutritive sweeteners possess a bacteriostatic effect and alter gut microbiota in mice. PLoS ONE, 13(7). https://doi.org/10.1371/journal.pone.0199080
12Pepino, M. Y. (2015). Metabolic Effects of Non-nutritive Sweeteners. Physiology & Behavior, 152(0 0), 450–455. https://doi.org/10.1016/j.physbeh.2015.06.024
Image Credits:
Fig 4.40. "Diet Hansen’s can" by 7 Bits of Truth is licensed under CC BY 2.0; "Sugar-free chocolate" by m01229 is licensed under CC BY 2.0; "Sweeteners" by sriram bala is licensed under CC BY-NC 2.0
Table 4.5. "Sugar substitutes" by Alice Callahan is licensed under CC BY-NC-SA 4.0
Fig 4.41. "Saccharin notice" by Linda Bartlett, National Cancer Institute is in the Public Domain
Fig 4.42. "Stevia" by Mike Mozart is licensed under CC BY 2.0
Having infrequent dry hard stool that is passed with difficulty and pain.
Small pouches in the wall or lining of any portion of the digestive tract that often cause pain