Physiological Roles

 

Proteins perform many important physiological roles. However, protein is not the only important nutrient because others are essential for the body to fully use available protein. Proteins are the principal source of nitrogen for the body and are fundamental components of all body cells. Proteins are necessary for many physiological functions, which can be classified into the following seven categories:

1. Generation of new body tissues. Because protein is a constituent of all cells, it is necessary for growth. During periods of increased growth (infancy, childhood, adolescence, and pregnancy) and in periods of wound healing or recovery (illness, surgery, burns, or fever), the need for protein to build new tissues is increased. In some individuals, moderately high protein consumption may stimulate muscle protein growth, favoring retention of lean muscle mass, while improving metabolism.
2. Repair of body tissues. Body proteins are continuously being broken down, necessitating their replacement. Assessment of recent and usual protein intake is important.
3. Production of essential compounds. Amino acids and proteins are constituents of regulatory enzymes, hormones, and other body secretions. The structural compound collagen is a protein substance of connective tissue that helps support body structures, such as skin, bones, teeth, and tendons. A low protein intake may affect all of these functions.
4. Regulation of fluid balance. Protein dissolved in water forms a colloidal solution; in other words, it attracts water. Blood albumin (a protein) draws water from interstitial (space between tissue cells) fluid or cells to maintain blood volume. During protein deficiency, a decreased amount of protein in the blood causes a loss of osmotic balance, resulting in an accumulation of interstitial fluid (edema)
5. Residence to disease. Antibodies, or immunoglobulins, the body’s main protection from disease, are proteins. Low protein levels may negatively affect and individual’s immune response, resulting in an inability to fight bacteria and other harmful organisms.
6. Transport mechanisms. Proteins enable insoluble fats to be transported through the blood.
7. Energy. When the nitrogen grouping is removed, the remaining carbon skeleton can be used for energy, furnishing 4 kcal/g. Although this is not one of its main functions, protein is used in this manner when (a) caloric intake from carbohydrate and fat is inadequate, (b) protein intake exceeds requirements, and (c) essential amino acids (EAAs) are unavailable for synthesis of proteins.

 

REQUIREMENTS

 

Protein requirements for health are based on body size and rate of growth. (The body needs more protein during growth periods or for maintenance and repair of a larger body mass.) To a certain extent, the better the quality of protein (higher PDCAA score), the less quantity is required. Protein requirements are based on the assumption that EAAs and kilocalories are provided in adequate amounts.

(Protein digestibility corrected amino acid (PDCAA) is the official method of evaluating protein quality for humans. It is based on amino acid requirements of young children and corrects for digestibility. Vegetable and some grain proteins are less well digested than animal protein, partly because the protein is encased in cell walls that make it less available to digestive enzymes. Vegetables and grains contain all the EAAs, but because one or more EAAs are present in a very low ratio, the protein they finish has a low PDCSS score.)

The recommended dietary allowances (RDAs) for protein vary proportionately for different ages and stages of life to adjust for growth rates. The Institute of Medicine (IOM) has determined the daily minimum requirement of protein for adults is about 0.6 g/kg. Using 0.6g/kg, a patient weighing 150 lb (68.2kg) would require 41 g of protein. Because RDAs provide a margin of safety, the IOM has established 0.8g/kg daily as the RDA. With this standard, a patient weighing 150 lb (68.2 kg) requires 56 g protein. The RDAs for protein for various stages of life are listed below.

 

Based on the National Health and Nutrition Examination Survey (NHANES), 2003-2004 data, protein intake averaged approximately 91g in adults 19 to 39 years old, and decreased to about 66 g/day in elderly adults. This represents approximately 15% of total kilocalories, within the recommended amount of acceptable macronutrient distribution range (AMDR) of 10% to 35%. Males consume more protein than females. Approximately 7% to 8% of adolescent girls and 7.2% to 8.6% of elderly women consume protein levels below their estimated average requirement. Very few individuals consume protein amounts close to the highest AMDR of 35% for their age/sex group.
   Recent research indicates many adults may benefit from eating more than the minimum requirement, and investigators have requested that the IOM revisit protein recommendations. The conclusions of the Protein Summit in 2007 were presented in the May 2008 Supplemental issue of the American Journal of Clinical Nutrition. Findings presented indicate higher protein diets are linked with a lower risk of chronic diseases, such as type 2 diabetes, coronary heart disease (CHD), and osteoporosis, and sarcopenia. Sarcopenia is the loss of muscle mass and strength with aging, a condition many believe is normal for elderly individuals.
   The conclusion of the investigators at the Protein Summit was that overweight or obese and older Americans may benefit by consuming 35% of their kilocalories from protein. It was also recommended that the revised 2010 Dietary Guidelines for Americans address protein as a required nutrient.
   When any condition of health or disease causes a significant protein loss, an increased protein intake (grater than the RDAs) prevents excessive loss of tissue and plasma proteins. Although these stares increase protein requirements, RDAs have not been established for these conditions. Providing additional amounts for supplementation with high-quality proteins can help prevent protein malnutrition and shorten recovery periods. While updating the macronutrients in 2002, the IOM reviewed scientific evidence for protein requirements for healthy adults undertaking resistance or endurance exercise. They found no compelling evidence for additional protein requirements, especially because Americans commonly ingest significantly more protein than is recommended.
   Ordinarily, dietary protein is restricted only in some physiological disease states affecting the liver and kidney because these organs are heavily involved in protein use and excretion of protein waste products. If the liver and kidney are diseased, excessive amounts of protein cannot be properly handled without further organ damage.

SOURCES

 Foods with a high protein content are readily available in the United States. Meat and milk food groups furnish most of the protein. Soy is a good source of protein and has other health benefits. An increased intake of cereal products boosts protein intake. The protein content of items from the sample menu displayed bellow.

 Food                                                 Quantity         Protein (g)

Chicken, light meat, cooked	2 oz	20
Chicken, dark meat, cooked	2oz	18
Pork chops lean, cooked	2oz	16
Beet, cooked, lean cuts	2oz	15
Pinto beans, cooked	1 cup	15
Cottage cheese	½ cup	14
Cheddar cheese	2oz	14
Cod fish, cooked	2oz	13
Egg, hard cooked	2	13
Thick milkshake	11 oz	12
American processed cheese	2oz	10
Milk, whole, reduced fat, or low fat	1 cup	10
Peanut butter	2 Tbsp	8
Nonfat dried skim milk powder	1/3 cup	8
Macaroni, cooked	1 cup	7
Oatmeal, cooked	1 cup	6
Rice, white, cooked	1 cup	4
Rice, brown, cooked	1 cup	5
Ice cream, l0% fat	1 cup	5
Corn muffin, small	1	4
Enriched white bread	1 slice	2
Vegetables	½ cup	1-2
Fruits	½ cup	0.1-1

 

Depending on sex, size, and activity level, MyPyramid recommends 5 to 7 oz of cooked lean meat, poultry, or fish daily for adults. About 3 Tbsp of chopped/ground meat, or the size of a small matchbox, equals 1 oz of meat; a small chicken drumstick or thigh is equivalent to 2 oz of meat; and a deck of cards or the size of your palm is approximately 3 oz. One-half cup, or the amount that can fit in a cupped hand, of beans or 1 Tbsp of peanut butter (size of a ping pong ball) can be substituted for 1 oz of meat. In most cases, digestibility and nutritional value are favorably affected by cooking procedures. Proper cooking sometimes facilitates digestion and use. Cooking makes egg albumin more readily digestible, and cooking soybeans increases amino acid bioavailability. Bioavailability indicates the amount of nutrient available to the body after absorption. Processing affects proteins in cereal by binding lysine (an amino acid), making it unusable by the body.

 

DENTAL HYGIENE CONSIDERATIONS

 

• Most Americans consume almost twice as much protein as
  recommended in the RDAs.
• When assessment indicates a normal consumption of 1.5 g/
  kg or more above the RDA for protein, this is considered a
  high-protein diet. Further increases may not be beneficial and
  may contribute to increased fat stores and dehydration.
• An inadequate protein intake could affect any or all of the
  physiological functions of protein in the body.
• Assessment of protein intake of patients with periodontal
  issues is especially important. Protein deficiencies may com-
  promise the physiological systemic response to inflamma-
  tion and infection, and periodontal problems may increase,
  the protein requirement to promote healing in patients with
  inadequate or marginal protein intake. 
• One rule of thumb is protein should provide 10% to 35% of
  caloric intake. If protein intake seems inappropriate, determine
  caloric or protein intake or both. The adequacy of intake can be
  established by using one of two methods. As an example, based
  on consumption of 2200 kcal/day, the amount of protein based
  on total energy intake is calculated as follows:

 

 2200kcal x 0.35 (maximum recommended % of total kilocalories from protein) =
   770 kcal from protein or less

 770kcal / 4 (kcal/g protein) = 193 or less of protein recommended

   The intake of 193 g of protein is the highest level recom-
mended. Because 35% is the upper limit, protein consump–
tion above this level may jeopardize adequate intakes of
nutrients provided from other food sources.
   For the second method for calculating, if protein intake is 55 g,
and caloric intake is 2200 kcal, the percentage of protein based on
the actual protein intake can be determined as follows:

 55 (g protein) x 4 (kcal/g protein) =
  220 kcal from protein

220(kilocalories from protein) / 2200
 (total kilocalorie intake)x 100(%) =
   10% of total kilocalories from protein

    Because 10%r is the lower limit, this person’s protein may
be inadequate, and professional counseling may be war-
ranted. Person should see a registered dietitian.

 To be continued…

 

Alcohol and cardiovascular disease

The studies regarding the beneficial effects of alcohol on heart disease risk remain controversial. No beneficial relationship was seen in the 6000 men who were followed for 20 years; in fact, an increased overall risk of mortality from all causes was seen in men who drank more than 22 drinks/week. In addition, men who drank more than 35 drinks/week had twice the risk of dying from stroke. Grape juice, rather than red wine, is probably a better choice for lowering blood pressure.

While it is reported that wine contains phytochemicals, which act as antioxidants, it is important to note that alcohol itself may cause oxidative stress that may damage the liver and pancreas. Alcohol causes an increase in triglycerides. At autopsy, the heart of a person who suffered from alcoholism will weigh twice as much as a heart of a nonalcoholic. Still, some researchers recommend a moderate alcohol intake for reduction of cardiovascular disease. At any rate, it is not recommended that a man consume more than two drinks/day or a woman more than one drink/day. 

Alcohol and cancer

A correlation exists between alcohol consumption and breast cancer in young women. In addition, relationships between alcohol usage and cancers of the liver, mouth, throat, esophagus, colon/rectum (especially in beer drinkers), and the lungs is documented. Once cancer has developed, alcohol appears to spur progression. 

Alcohol and the elderly

Having an alcoholic drink 20 minutes before mealtime is shown to improve appetite. It also seems to improve morale, stimulate sociability, and help with sleep. Improved staff-resident relations are reported in nursing homes that allow residents to drink a moderate amount of wine. 

Alcohol and the brain

The brain shrinks in people who drink moderately or excessively. The extent of the shrinkage correlates to the amount of alcohol consumed. Alcoholics who abstain from all alcohol and eat a healthful diet can reverse some, or all, of the brain damage. However, the damage is sometimes irreversible, if the person has drank alcohol in excessive amounts for a long time, and permanent harm to memory, vision, and learning ability may occur. 

Alcohol and mineral loss

The dehydration caused by alcohol consumption may lead to deficiencies of magnesium, selenium, phosphorus, potassium, calcium, and zinc, if proper nutrition is ignored. A long list of health issues may result from these deficiencies, including damage to the nervous and muscular systems and inappropriate fluid balance. 

Other nutritional issues associated with alcoholism

• Failure to absorb thiamine, vitamin B12 , and vitamin B6 (in addition to the destruction of existing B6)
• Failure to activate vitamin D
• Failure of rod cells in the retina and liver cells to process vitamin A
• Expulsion of folate from storage and excretion into the urine, in addition to an inability of the intestine to retrieve any—folate deficiency is the cause of Wernicke-Korsakoff syndrome in alcoholics
• Protein-energy malnutrition
• Scurvy

Alcohol and the liver

Alcohol causes the liver to make more fatty acids, which results in fat accumulating in the liver, even after a single night of heavy drinking. Of course, if a person is not drinking heavily every night, within a few days the fat will clear out of the body. However, in heavy drinkers, fatty liver is the first stage of liver damage.

If a person has a fatty liver for long enough, fibrous scar tissue will form, known as fibrosis. Even fibrosis is curable with abstinence and a healthy diet. However, if a person continues to drink, cirrhosis develops, which has no cure. With cirrhosis, the liver cells die and the body cannot regenerate them. 

Other health conditions associated with alcohol abuse

• Ulcers
• Nonviral hepatitis
• Kidney, bladder, pancreas, and prostate damage
• Impaired immunity
• Sexual impotence in men
• Reproductive issues in both sexes
• Bone deterioration and osteoporosis
• Central nervous system damage

Determining how much alcohol is in your drink

The percentage of alcohol is stated as “proof.”  Proof equals twice the amount of alcohol in the drink. For example, 100-proof liquor is 50% alcohol. A standard serving of alcohol delivers ½ fl oz of ethanol. One standard drink is:

o        Wine: 3-4 fl oz

o        Wine cooler: 10 fl oz

o        Beer: 12 fl oz

o        80-proof whiskey, gin, brandy, rum, or vodka: 1½ oz

Unless you are mixing your own drinks, it is hard to determine how much ethanol each drink contains. It is important to note that a woman will absorb one third more alcohol than a man of the same size. 

Alcohol and weight
 

• Alcohol should count as a “fat” in the diet, even though many alcoholic beverages are fat free, because alcohol most likely promotes fat storage, which leads to the “beer belly” effect that we have all have heard about. Alcohol contains 7 calories of energy/gram (g). Carbohydrate and protein contain 4 calories/g, and fat contains 9 calories/g.
• To calculate how many calories are in a drink, use the following equation:
  • calories=fluid ounces (fl oz) of beverage x proof x 0.8 calories

 

Calories in common beverages

Beverage	Calories
Wine, dry red or white (4 fl oz)	85
Bloody Mary (5 fl oz)	116
Beer, regular (12 fl oz)	150
Martini (2½ fl oz)	156
Whiskey sour (4 fl oz)	164
Gin and tonic (8 fl oz)	182
Wine cooler (12 fl oz)	215
Daiquiri (4 fl oz)	222
Piña colada, no ice (4 fl oz)	228
Margarita, no ice (4 fl oz)	267

 

  

References and recommended readings

Sizer F, Whitney E. Alcohol and nutrition. In: Graham L, ed. Nutrition Concepts and Controversies (annotated instructor’s edition). Belmont, CA: Wadsworth/Thompson Learning; 2000:167-174.
 

US Dept of Agriculture, Agricultural Research Service. What’s in the Food You Eat search tool. Available at: http://www.ars.usda.gov/Services/docs.htm?docid=7783. Accessed September 13, 2008.

    Many consumers are unaware how beneficial nuts, beans, and seeds can be when it comes to getting the proper amount of nutrients in your diet. In the February 2012 issue of Food Technology magazine, published by the Institute of Food Technologists (IFT), contributing editor Linda Milo Ohr writes that heart health, weight management, healthy cholesterol levels, and cognitive health are just some of the benefits that these foods can offer.

   Almonds are low in saturated fatty acids, rich in unsaturated fatty acids, and contain fiber, phytosterols and plant protein. In a scientific review, Berryman et al. (2011) showed that consuming a breakfast containing almonds aids in stabilizing blood glucose levels for most of the day and provides a lasting feeling of fullness. Pistachios are also considered a part of a heart-healthy diet and may also lower cholesterol. In addition some research has shown that walnuts may have been linked to benefits related to brain health and cancer.

   Beans, also called legumes, also play an important role in diet. They contribute complex carbohydrates, vitamins, fiber, minerals and antioxidants that may help lower the odds of cognitive deficits or the risk of Alzheimer’s disease. Pulses like dry peas, lentils, and chickpeas are also members of the legume family and contain both fiber, protein, as well as seven of the eight essential amino acids needed in the body.

   Chia seeds, sunflower seeds, and hemp seeds also contribute a myriad of essential minerals and amino acids to the human diet. Chia seeds can be mixed with liquids to create sports drinks for athletes with omega-3s to address inflammation and protein to help with muscle recovery.

These suggestions will help you choose the correct exercise plan to meet your needs.

The Seven Major Components of Fitness

• Body composition
• Cardio-respiratory function
• Flexibility and range of motion
• Muscular strength
• Endurance
• Balance
• Agility and coordination

 

Yoga, Tai Chi, and Pilates

• Reduction of muscular tension
• Injury prevention
• Body relaxation
• Strengthening of the skeletal system
• Enhancement of circulation
• Immune system boost
• Reduction of symptoms of chronic disease, especially arthritis, diabetes, and thyroid disorders
• Mood improvement
• Increased flexibility
• Improved muscle tone 

Amount needed for benefit — at least three times/week.

Aerobics (swimming, power walking, running, cycling, dancing, and in-line skating)

• Improvement of heart, lungs, and circulatory system functioning
• Better processing of oxygen and more effective transporting to muscle
• Burning of calories and body fat
• Increase in metabolism
• Decrease in blood pressure and risk of heart disease
• Help in prevention of diabetes
• Strengthening of skeletal system
• Strengthening of immune system
• Improvement in sleep
• Reduction in risk of cancer, especially breast, prostate, and colon cancers
• Possible improvement in cognitive function and help in prevention of memory loss
• Reduction in overall mortality
• Mood improvement
• Injury prevention

Amount needed for benefit — 30 minutes of moderate exercise 5 days/week, and if you want to lose weight, exercise more often or at higher intensity (you have to burn 3500 more calories than you take in to lose a pound). Some experts recommend purchasing a heart monitor and aiming at 30 minutes at 60% of maximum heart rate/day.

Anaerobic (weight lifting and calisthenics)

• Help burning more calories, even at rest, by increasing metabolism
• Bones become denser and less prone to osteoporosis and injury
• Protection for  joints against wear and tear
• Reduction in arthritic pain
• Injury prevention
• Muscle loss delay and building of muscle mass
• Improvement in glucose tolerance and reduction in risk of diabetes development
• Mood improvement

Amount needed for benefit — 3-4 days/week, not exercising the same muscle group 2 days in a row.

Before choosing a plan

Take into account these considerations before choosing an exercise plan:

• How much you like exercising around other people will determine whether or not you should try a new fitness class, as some people feel self-conscious in group environments.
• Some people become bored or distracted if attempting exercise without an instructor, a timer, or other people nearby to keep them interested. If you are this type of person, but still want to exercise in the comfort of your own home, consider investing in fitness DVDs or making your own mix of music to keep you mentally involved in the activity.
• Some people need a goal in mind before starting a program. This goal varies according to the individual. For the athletically inclined, it could mean running a marathon. A less cardio-fit person may set a more reasonable first goal for themselves, such as walking up four flights of steps without feeling short of breath. Whatever your goal is, make the goal specific and something you can visualize easily. Then, you can consistently remind yourself of it before stepping onto the treadmill or beginning your sun salutations. 
• Thrill-seekers naturally stick to routines that reflect their adventurous side, such as kayaking, mountain biking, or snowboarding. If you are not one of these people, you should never attempt to force yourself to try these activities without testing the water first.
• Recent studies have shown that breaking your aerobic exercise into 10-minute spurts throughout the day works as well as doing a full-length session at one time. However, this approach does not work for everyone, as some people skip their 10-minute spurts or begin to overestimate their level of physical activity throughout the day.

 

References and recommended readings

Well R. Aerobic exercise. Available at: http://www.medicinenet.com/aerobic_exercise/article.htm. Accessed October 19, 2008.  

Zelman K. Benefits of exercise. Available at: http://www.medicinenet.com/benefits_of_exercise/article.htm. Accessed October 19, 2008. 

Weight Awareness. Comparing exercise programs. Available at: http://www.weightawareness.com/topics/doc.xml?doc_id=1361&__topic_id=1114. Accessed October 19, 2008.

Jordan J. Yoga. Available at: http://www.nywellnessguide.com/yoga/  Accessed October 19, 2008.

 Review Date 11/08

G-0860 

 

 

A common misperception is that sugar is uniquely fattening.Because the taste of sugar is so pleasant, some rationalize that sugar becomes irresistible to the point of overconsumption or addiction. However, most individuals have a limit as to how sweet they like their foods and how much they can consume in a given period.
   No evidence exists that carbohydrates or sugars are a cause of obesity. A higher intake of whole grains (about three servings daily) was associated with healthier body weights and tat stores. Excessive caloric intake leads to obesity, whether from carbohydrates, proteins, fats, or alcohol. Although excessive energy intake from sugar may lead lo obesity, epidemiological studies and several individual studies have shown that obese patients actually consume less sugar than thin patients. Many sweet foods contain large amounts of fat. Too much carbohydrate is likely to be consumed when fat is limited and overall food intake is not restricted to some degree.

Dental Considerations

Scientific studies do not support the claim that sugars interfere with bioavailability of vitamins, minerals, or trace nutrients, or the notion that dietary imbalances are preferentially caused by increased sugar consumption. Do not assume that because a person is obese, increased sugar intake is the culprit.

 Nutritional Directions

• A well-balanced diet that contains adequate nutrients with appropriate amounts of fruits and vegetables and milk and dairy products is advisable.
• Several organs depend on glucose to function. A change to a minimal-carbohydrate, high-protein, high-fat diet may result in an inadequate intake of numerous nutrients.

 

SUGAR SUBSTITUTES

The practice of flavoring foods without additional kilocalories is one of many approaches to the problems of excess energy intake and a sedentary lifestyle. The use of sugar substitutes also has beneficial ramifications for dental hygiene. The desire to decrease sugar consumption is being met through widespread and increasing use of numerous sugar substitutes. Consumption of low-calorie sweeteners is increasing faster than that of caloric sweeteners.
   These products are used principally for their sweetening power, but they also make some foods more palatable. The large variety of sweeteners is desirable because each has certain advantages and limitations. Because each sweetener has different properties, the availability of various products helps satisfy various flavor and texture requirements in foods and beverages. Sweeteners may be combined because of their synergistic effect—that is, when combined, sweeteners yield a sweeter taste than that provided by each sweetener alone.
   Although taste buds may be fooled by their sweetness, non-nutritive sweeteners do not produce a prolonged feeling of satiety and could prompt overeating. An emerging body of scientific evidence suggests artificial sweeteners offer little help to dieters and may help promote weight gain. Concerns have been expressed that nonnutritive sweeteners may promote energy intake and contribute to obesity. Most of the possible mechanisms by which this occurs are not supported by available evidence. Resolution of this important issue will require long-term randomized controlled trials.
   Use of these non-nutritive sweeteners may or may not decrease the total kilocalorie intake, depending on other food choices. Making compensatory food choices, such as drinking a diet carbonated beverage to permit a piece of cheesecake, is ineffective in weight control, whereas replacing a high-calorie food with a low-calorie food, watching other food intake, and engaging in some form of exercise may be beneficial.
   Many people question the safety of these products. All products on the market have been extensively researched and are safe for most people if consumed in moderation except for aspartame. Aspartame should be avoided by patients who havephenylketonuria, a genetic disorder characterized by an inability to metabolize the amino acid phenylalanine.

Dental Considerations

• Sugar substitutes can reduce the energy content and decrease cariogenicity of a product. Used in moderation, sugar substitutes are beneficial for many people, especially patients with diabetes.
• Because aspartame contains phenylalanine, aspartame-containing products are labeled to warn patients with phenylketonuria to avoid their use.
• Use of sugar substitutes is especially advocated for between-meal snacks to decrease frequency of exposure of the teeth to sugar. For individuals who do not need to decrease energy intake, sugar alcohols may be recommended.
• Sugar substitutes are nonfermentable and do not promote caries formation; antimicrobial activity has not been observed. Saccharin and aspartame exhibit microbial inhibition and caries suppression.

 

Nutritional Directions

• Non-nutritive sweeteners may not have cariogenic potential. However, bulking ingredients that allow them to pour and measure more like sugar and other constituents of a product may have cariogenic potential because of the presence of fermentable carbohydrates.
• Non-nutritive sweeteners do nothing to appease the appetite, but they do provide the pleasure of sweetness. They may enable people to choose a wide variety of foods while managing their caloric or cariogenic intake.
• When deciding whether a young child should be given foods sweetened with a non-nutritive sweetener, consider the child’s body weight, and limit the sweetener to below recommended levels (500 mg/day for saccharin, 50mg/kg body weight for aspartame, and 15mg/kg body weight for Acesullame-K).
  One packet of Sweet’n Low (Cumberland Packing Corp) contains 40 mg of saccharin; one packet of Sweet One (Stadt Corp), 50 mg of acesulfame; and one packet of Equal (Nutrasweet Co), 35 mg of aspartame. (Because there are no known side effects for sucralose, no maximum limits have been established for children). Remember, children need energy for growth and development.
• Combinations of sweeteners can produce a sweet taste more similar to that of sugar than can a single high-intensity sweetener.
• During pregnancy, saccharin is not recommended because it is known to cross the placenta. Refer a pregnant patient to her obstetrician for counseling about use of any non-nutritive sweeteners.

Health Application – High-Fructose Corn Syrup

In recent years, the lay press has drawn a lot of attention to several studies regarding high-fructose corn syrup (HFCS)and its association with the current obesity epidemic, diabetes mellitus, and other maladies. HFCS has been labeled “the devil’s candy.” “the crack of sweeteners,” and “a sinister invention.” Consumers are specifically concerned about HFCS; many of their changes in food choices are driven by an effort to lose weight.
    HFCS was so named because it is made from corn; however, it is different from regular corn syrup, which is composed of glucose and glucose polymers. Some of the glucose molecules in corn are changed into fructose, making MFCS sweeter. The enzymatic processes involved in the production of HFCS are used to produce other foods and ingredients that are considered natural. The U.S. Food and Drug Administration (FDA) has stated that HFCS may be labeled as a natural ingredient.
   HFCS has a ratio of fructose to glucose identical to sucrose and honey; in other words, it contains nearly equal amounts of fructose and glucose. It is comparable to sugar and honey in its sweetness and the way it is processed in the body. It was designed to be equal to sucrose in sweetness so that they could be used interchangeably in foods and beverages. HFCS has been used principally in carbonated beverages and fruit preparations because of its stability in acidic products. After fructose and glucose (from sucrose, HFCS, or honey) are absorbed from the intestinal tract, each enters into its own metabolic pathway, just as the fructose and glucose molecules from sucrose. After fructose and glucose reach the bloodstream, the human body cannot distinguish these sweeteners from one another. Many studies have shown that HFCS does not prompt the production of hormones that help regulate appetite and fat storage, and scientific evidence does not indicate that HFCS alters metabolism uniquely to promote deposition of body fat. Fructose can produce elevated levels of triglycerides, which have been linked to an increased risk of heart disease.
   The Center for Food, Nutrition and Agriculture Policy organized an expert panel to discuss the relationship between the consumption of HFCS or “soft drinks” and weight gain. After studying the published scientific literature, the expert panel concluded that HFCS does not seem to contribute to overweight and obesity any differently than do other energy sources.
   HFCS currently accounts for about 10% of sweetener used around the world. Many other countries are seeing increasing rates of obesity and diabetes even though little or no HFCS is present in their food supply. As a result of the availability of HFCS, sucrose use has declined from 80% of total caloric sweetener in 1970 to 40% in 1997. Body mass index (BMI) values continued to increase between 1997-2004, whereas per capita consumption of HFCS remained stable. Over consumption of either sweetener, or any caloric-containing food or beverage, along with fats and decreased physical activity contribute to weight gain.

For many years, sucrose, the most frequently consumed form of sugar, has been considered the “arch-villain” in dental caries formation. Sucrose and other carbohydrates have unusual biochemical properties that promote bacterial growth. The presence of sucrose and other carbohydrates in the mouth increases the volume and rate of plaque biofilm formation. Even low amounts of sucrose in the mouth promote production of polysaccharides (glucans) by Strep­tococcus mutans, the bacteria that facilitate adherence of plaque biofilm to a tooth. These glucans help provide a matrix supporting communities of microorganisms collec­tively referred to as plaque biofilm. Sucrose can lower the pH of plaque biofilm, hastening the dissolution of hydroxyapatite crystals of the enamel. Glucose available from sucrose or any other carbohydrate food can be used for energy by oral bacteria in plaque biofilm.
   Many health professionals and consumers falsely believe that removing sucrose from the diet would largely eliminate dental caries. The American Dental Association (ADA) rec­ognizes carbohydrates provide energy required for optimal nutrition. However, the ADA has recommended fermentable carbohydrates consumed frequently or repeatedly (chewable tablets, cough drops, breath mints) be replaced with products containing noncariogenic sweeteners, preferably xylitol.
   Despite differences in the carbohydrate content of car­bonated beverages, fruit drinks, juices (about 10% carbohy­drates), sport drinks (about 46% to 48% carbohydrates), energy drinks (about 9% to 10% carbohydrates), flavored coffees and teas, and powdered drinks, all of these beverages seem to have similar cariogenic potential. Although federal regulations prohibit sale of soft drinks to students during lunch in most high schools, vending machines are accessible to students throughout the day. Adolescent boys consume an average of 1.5 cans of soda daily, and teenage girls consume 1 can a day. Regular sodas and energy drinks contain fermentable carbohydrates and are highly acidic. Tooth erosion occurs when the enamel gradually dissolves and the outer layer is removed with fre­quent exposure to acidic liquids. Research suggests enamel erosion with various beverages occurs in the following order: energy drinks, sports drinks, regular soda, and diet soda.

   Other monosaccharides and disaccharides, such as glucose, fructose, maltose, and lactose, are also readily metabolized by oral microorganisms, with resultant demineralization of tooth enamel. These sugars diffuse rapidly into plaque biofilm to become available for bacteria. In labora­tory tests, fructose and glucose rapidly lower plaque biofilm pH similar to sucrose; they are considered as cariogenic as sucrose. Substituting glucose or fructose for sucrose would not be significantly effective in reducing caries rates. Lactose is less cariogenic than other sugars. The kind of sugar is not significant; the concentration or quantity of sugar in a food­stuff is not critical to its cariogenic potential.
   Most studies of large populations have correlated caries rates with total sugar consumption. Conversely, no clear-cut relationship has been shown between total carbohydrate consumption of individuals and caries. Starches can cause acid production in the plaque biofilm when consumed as part of a mixed diet containing fermentable carbohydrates. Some foods, such as potato chips or crackers, containing a high-carbohydrate, low-sugar content can be active participants in the caries process when salivary amylase hydrolyzes the complex carbohydrate to simple sugars. The starch molecule is large and cannot penetrate into plaque biofilm. Cooked and refined cereal grains are readily hydrolyzed by salivary amylases to produce maltose, which can lower the pH and demineralize enamel. Some foods high in sugar are removed quicker and do not lower the pH of plaque biofilm as much as starchy foods with less sugar. Starches, such as breads and pasta, are considered less cariogenic than sugars, but may tend to prolong the caries attack after it has been initi­ated, especially when sugar is added, as in sweet breads and cookies.
   The total amount of dietary fermentable carbohydrate seems to be of less importance than the form in which it is eaten and the frequency of consumption. This may be related to variables influencing the length of time carbohydrate is in contact with the teeth and its potential for promoting growth of caries-forming, acid-producing bacteria.
   Because of the belief that sucrose restriction would curtail dental caries, some popular snack products contain sweeten­ers that are less cariogenic than sucrose. Sugar alcohols may decrease the risk of dental caries through any of the follow­ing mechanisms: (1) inhibiting the growth ofS. mutans, (2) not promoting the synthesis of plaque biofilm, or (3) not lowering plaque biofilm pH. The ADA has approved the use of the ADA seal on sugarless gums by a gum manufacturer, based on several studies. One study using sugarless gum showed 8% fewer cavities over a 3-year period, and another study showed a 39% decrease in caries over a 2-year period.
   Sorbitol causes only a slight pH decrease in plaque biofilm. Bacteria in plaque biofilm are able to ferment sor­bitol and mannitol, but only at a very slow rate over several weeks. After a period of adaptation, however, acid produc­tion increases.
   Xylitol is anticariogenic because oral bacteria lack the enzymes to ferment it; plaque biofilm pH does not decrease. An anticariogenic substance reduces the risk of caries by preventing bacteria from recognizing a cariogenic food. Xylitol stimulates secretion of saliva, which contains a larger number of bicarbonate ions to neutralize acid. Xylitol may inhibit growth of S. mutans. Certain mixtures of sorbitol and xylitol may be more protective against dental caries than sorbitol alone.
   Lactitol cannot be metabolized by bacteria in plaque biofilm and may provide a protective effect for teeth. However, it is only about one-third as sweet as sucrose. Saccharin inhibits tooth decay in rats. Aspartame does not support the growth of S. mutans, acid production, or plaque biofilm formation.

Dental and Nutritional Considerations

• Approximately 90% of commonly consumed snack foods contain fermentable carbohydrates (sugars or cooked starch or both).
• Snacks contribute significantly to the nutritional intake of young children and teenagers, who need larger amounts of energy for growth.
• Patients unable to tolerate adequate amounts at meals require snacks to promote healing and avoid loss of lean tissue.
• Although sucrose is a major factor in caries risk, provide factual information that does not over blame or over claim sugar’s role in caries formation. 
• Some foods, such as milk and aged cheese, actually protect the teeth by increasing the pH of the mouth and inhibiting acid production. If snacks are needed when oral hygiene cannot be performed, suggest snacks consisting of low-fat milk products or aged cheese.
• Total elimination of sweets permanently is unrealistic. The best advice is to (1) use sugar in moderation, (2) limit the frequency of sugar exposure, and (3) brush the teeth after consuming sugar-containing products. If brushing cannot be performed, chew xylitol-containing gum.
• Encourage nutrient-dense beverages (100% fruit juice, milk) and water as a part of a varied diet.
• Excessive intake (more than 20 g per day) of sorbitol-containing sugar-free gum and sweets may lead to unintended weight loss as a result of chronic diarrhea. One stick of sugar-free gum contains about 1.25 g sorbitol.

 

Nutritional Directions

• People can maintain healthy teeth and still include sweet-tasting foods without increasing the risk of caries.
• The most important cause of dental caries is the frequency of intake of fermentable carbohydrates, which supply sub­strate to the caries-producing oral bacteria.
• The potential for caries exists every time a carbohydrate is eaten because most foods promote acid formation if no procedures are taken to remove food debris or plaque biofilm, to buffer the acid produced, or to interfere with acid production.
• The amount of carbohydrate in a food is unrelated to its caries-forming potential; all carbohydrate foods are poten­tially cariogenic. Proteins and fats are cariostatic, or cannot be metabolized by microorganisms in plaque biofilm, and are caries-inhibiting.
• Natural sugars, primarily fructose and glucose, in unpro­cessed foods, such as bananas and raisins, are potentially as cariogenic as sucrose.
• Vegetables such as lettuce, celery, and broccoli contain car­bohydrate (5 g per serving), but do not cause acid production or demineralization of enamel in humans.
• Sugar alcohols are less likely to promote caries; xylitol seems to prevent caries formation.
• Highly acidic foods may prevent bacterial fermentation, but cause enamel erosion.
• Replacing potentially cariogenic snacks with foods such as fresh fruits and vegetables; low-fat cottage cheese, cheese, and yogurt; peanuts; or low-fat popcorn can decrease caries and promote other health-conscious nutritional habits.
• To prevent dental caries, (1) always brush after eating, and (2) eat fermentable carbohydrates as part of a meal rather than as snacks.
• Using a straw with beverages such as carbonated drinks may lessen contact with the teeth and may lessen the risk of caries.
• Consumption of sodas should be limited to 8 oz or less daily with a meal. If brushing teeth after drinking the soda is not possible, rinse the mouth with water or chew gum containing xylitol.
• High-carbohydrate foods, especially complex unrefined carbohydrates, are high in fiber and other nutrients.