The Recommended Dietary Allowances (RDAs) were first established in 1941 by the Food and Nutrition Board. At that time, nutrition science was still in its infancy: thiamin was the first vitamin to be isolated in 1926; the first Nobel Prize for vitamin discovery were awarded in 1928. The RDAs were developed to aid the American public in following a diet that would provide enough nutrients to prevent vitamin deficiencies. To keep up with the advancements in nutrition science, the RDAs have been updated every 5 years until the 10th and last edition was published in 1989. This final edition delivered recommendations for nutrient intake for protein, 13 vitamins, 12 minerals and 3 electrolytes; these recommendations were provided for 18 life stages and different groups based on gender, age and life stages (pregnancy and lactation) (Lee & Nieman, 2013). The RDAs guidelines have also been used for food labeling, food planning, dietary survey data and other purposes for which they were not originally intended.
The biggest limitation of RDAs consisted in the fact that its dietary guidelines aimed at preventing nutrient-related diseases instead of obtaining and maintaining optimal health. For this reason, in the 1990s the RDAs guidelines were broadened and collected in what is known as the Dietary Reference Intakes (DRIs) discussed below.
Recommended Daily Allowances
The Dietary Guidelines are different than the RDAs in multiple ways: the RDAs give recommendations for 18 life stages and different groups based upon gender, age and life stages (pregnancy and lactation). The Dietary Guidelines has only one set of recommendations for all individuals over the age of 2 and therefore needs to work across a wide range of energy needs. Most Dietary Guidelines are given either as a percentage of total calories or as a recommendation for a nutrient in a certain amount for every 1,000 calories consumed. Another major difference between RDAs and Dietary Guidelines is that there is an RDA for every essential nutrient while the Dietary Guidelines only provide recommendations for those nutrients that are linked to diet-related chronic diseases. For example, the RDA for carbohydrates in adults is 130 grams, while the Dietary Guidelines for carbohydrates is 45-65% of total calories. When nutrition professionals assess a patient’s intake for carbohydrate they look at both references: the use RDAs to look for the amount needed to meet nutrient demands, and they also use the Dietary Guidelines to assess amounts of carbohydrates needed to reduce incidence of diet-related chronic disease.
The Dietary Reference Intakes (DRIs) were first published in 1997 as the result of a collaboration between the Food and Nutrition Board and the Canadian Government. Canadian and American scientists worked together for over two years to bridge the gap between the information provided by the RDAs and the nutrition information the public needed and wanted. The initial report covered only 5 nutrients, but following reports spanning a decade were expanded to include guidelines on all vitamins and minerals, as well as macronutrients, hydration, fiber intake and exercise. The DRIs are updated as new information becomes available.
The DRIs are a collection of nutrient standards. They maintained the RDA’s focus on preventing nutrient deficiencies and added other standards: The Tolerable Upper Limit (UL) and the Acceptable Macronutrient Distribution Range (AMDR). The UL provides a standard for excess intake, while the AMDR provides a guidance on the percentage of calories from the different macronutrients that aligns with consuming adequate nutrient intake.
Dietary Guidelines
The Dietary Guidelines for Americans were first published in 1980 and have been updated every 5 year since. The purpose of the Dietary Guidelines is to provide nutrition recommendations with a focus on preventing chronic disease and to promote healthy eating and exercise habits to “improve the health of our Nation’s current and future generations” (McGuire, 2011).
The Dietary Guidelines are different than the RDAs in multiple ways: the RDAs give recommendations for 18 life stages and different groups based upon gender, age and life stages (pregnancy and lactation). The Dietary Guidelines has only one set of recommendations for all individuals over the age of 2 and therefore needs to work across a wide range of energy needs. Most Dietary Guidelines are given either as a percentage of total calories or as a recommendation for a nutrient in a certain amount for every 1,000 calories consumed. Another major difference between RDAs and Dietary Guidelines is that there is an RDA for every essential nutrient while the Dietary Guidelines only provide recommendations for those nutrients that are linked to diet-related chronic diseases. For example, the RDA for carbohydrates in adults is 130 grams, while the Dietary Guidelines for carbohydrates is 45-65% of total calories. When nutrition professionals assess a patient’s intake for carbohydrate they look at both references: the use RDAs to look for the amount needed to meet nutrient demands, and they also use the Dietary Guidelines to assess amounts of carbohydrates needed to reduce incidence of diet-related chronic disease.
Type-2 diabetes is a chronic metabolic condition that affects an estimated 425 million people worldwide. It is one of the biggest public health problems, and this already high number is estimated to surpass 600 million cases by 2045. Type-2 diabetes is a disease of lifestyle that affects the way the body metabolizes glucose. People who suffer from type-2 diabetes have either an inability to effectively utilize insulin or do not produce enough insulin to maintain a glucose level within the normal range of 70-100 mg/dL. Type-2 diabetes is also known as diabetes mellitus type2, noninsulin-dependent diabetes mellitus (NIDDM), and adult-onset diabetes. It used to be known as adult-onset diabetes because, formally, it was diagnosed in adults over the age of 45. Nowadays, unfortunately, type-2 diabetes is more and more prevalent in children as well, and, according to the National Diabetes Statistics Report, 193,000 children and teenagers under the age of 20 have been diagnosed with diabetes in 2015 (type-1 and type-2).
Healthy Blood Sugar Metabolism
In normal blood sugar metabolism, the beta cells of the pancreas produce and release insulin in response to the carbohydrate portion of a meal. Insulin is responsible for shuttling glucose away from the bloodstream and into liver and muscle cells. With repetitive excess glucose, cell receptor sites become resistant to insulin, causing glucose to remain in the bloodstream and build up to dangerously high levels. Therefore, type-2 diabetes is linked to insulin resistance. Additionally, as blood sugars remain elevated, the pancreas is forced to produce and release more insulin, which eventually puts a strain on the organ.
How Is Type 2 Diabetes Different From Type 1 & Gestational Diabetes?
There are two other types of diabetes: type-1 diabetes and gestational diabetes (GD). Type-1 diabetes is an auto immune disorder in which the beta cells of the pancreas are attacked and destroyed by the immune system. People with type-1 diabetes produce little to no insulin and become insulin-dependent for the rest of their lives. The damage is irreversible. Gestational diabetes only occurs in pregnancy. It affects 2 in 10 pregnant women, and it is generally diagnosed between the 24th and the 28th week of gestation. GD is caused by pregnancy hormones (namely, human placental lactogen) that cause the body to become insulin resistant.
It was originally thought that type-2 diabetes could not be cured and was genetic in nature. Medicine and nutrition are evolving sciences, and we now know that while there can be a genetic component to type-2 diabetes, it is mainly a disease of lifestyle. Risk factors may include family history, race (Black, Hispanics, American Indians, Asians Americans are at higher risk), age, low activity level, fat distribution (accumulation of abdominal fat), and body weight. Other medical conditions linked to developing type-2 diabetes are prediabetes, PCOS, and gestational diabetes. Women with gestational diabetes are at higher risk of developing the developing type-2 diabetes in their lifetime. Also, women who deliver babies weighing more than 4 kg have a higher risk of developing type-2 diabetes.
Symptoms Of Type 2 Diabetes
Symptoms of type-2 diabetes are unintended weight loss, increased thirst, frequent urination, increased hunger, fatigue, blurred vision, slow-healing sores, frequent infection, darkening of skin usually in the areas of the armpits and neck. Diabetes has serious long-term complication that are disabling and life-threatening. They range from stroke to heart disease, to high blood pressure and atherosclerosis, neuropathy, kidney damage, slow healing and infections, skin conditions (including bacterial and fungal infection), hearing impairment, sleep apnea, eye damage and blindness. In recent years, type-2 diabetes has been linked to increased risk of Alzheimer’s disease, which is now called by some type three diabetes.
Type-2 diabetes is diagnosed using the glycated hemoglobin (A1C) test. This test indicates average glucose levels for the past three months. Normal levels are below 5.7%. A result between 5.7 and 6.4% is considered prediabetes. A A1C result of 6.5% and above on two separate tests is considered diabetes. When A1C is not available, physicians may use a random glucose test, a fasting glucose test, or a glucose tolerance test. The latter is the preferred test used to check for gestational diabetes.
How Does Conventional Medicine Approach Type 2 Diabetes?
Conventional medical treatment is based on the use of medication to improve blood sugar control. Medications come with side effects and drug interactions. Most medications for type-2 diabetes are oral drugs while a few are injectable. Patients who are not able to manage their blood glucose through oral medications may require insulin injections as well. There are several classes of diabetes medications: alpha-glucosidase inhibitors aid in the breakdown of starches and sugars. Biguanides decrease intestinal absorption of glucose, help muscles absorb glucose, and decrease the amount of glucose that the liver makes. Metformin is a biguanide. This medication comes with a host of side effect which affect the gastrointestinal tract, including abdominal pain and diarrhea. Dopamine agonist is another type of medication, though its mechanism is still not understood. Dipeptidyl Peptidase-4 inhibitors (DPP-4) help the pancreas make more insulin, and they also reduce blood sugar without causing hypoglycemia. Glucagon-like peptide 1 receptor agonists (GLP-1) mimic the natural hormone incretin by stimulating the growth of beta cells and decreasing appetite. GLP-1 receptor agonists also influence glucagon utilization. Meglitinides help the body release insulin, though they may cause hypoglycemia and need to be prescribe with caution. Sodium-glucose cotransporter-2 inhibitors (SGLT 2) prevent the kidneys from holding onto glucose and promote glucose excretion through urine. Sulfonylureas stimulate pancreatic insulin production. Thiazolidinediones help fat tissue utilize insulin more efficiently, and they decrease glucose in the liver.
It is important to note that people suffering from type-2 diabetes also are often affected by other conditions like heart disease, high blood pressure or high cholesterol, and, therefore, the choice of medication(s) for treatment of type-2 diabetes must be based on the patient’s complete clinical picture. For example, GLP-1 receptor agonists are usually preferred for diabetes patients affected by cardiovascular disease, heart failure or chronic kidney disease. As stated above, these medications come with side effects. They also cause depletion. For example, medication like glyburide, glipizide, and chlorpropamide deplete CoQ10, while metformin depletes vitamin B12.
Nutrients That May Be Linked To Type 2 Diabetes
Nutrients that are linked to the development of type-2 diabetes, or are found in insufficient levels in people suffering from a type-2 diabetes, are vitamin A, magnesium, vitamin D and chromium. Vitamin A boosts beta cell activity, and new research points to vitamin A insufficiency as playing a role in developing type-2 diabetes. Low magnesium levels, both intracellular and extracellular, are generally associated with type-2 diabetes. Insulin and glucose are important for magnesium metabolism, and magnesium has a key role in regulating insulin action, glucose uptake, and vascular tone. Studies confirm that low vitamin D level is a risk factor for type-2 diabetes. Low vitamin D is linked to beta cell disfunction, insulin resistance, and systemic inflammation all of which can contribute to type-2 diabetes. Chromium is an essential trace mineral important for insulin regulation as well as for carbohydrate and lipid metabolism. Supplementation with chromium picolinate has been shown to reduce insulin resistance and to lower risk of cardiovascular disease and type-2 diabetes.
What Happened To Diabetics Before Injectable Insulin?
Before the advent of diabetes medication and injectable insulin the treatment of choice was a reduced carbohydrate diet. For decades, after the introduction of drugs, the medical establishment would prescribe a low-fat diet comprised of at least 40% to 50% of carbohydrates. However, the past few years have seen a shift in the nutrition therapy treatment proposed by the medical community. New evidence-based approaches are being developed, and different diets like the low carbohydrate diet and the Mediterranean diet are being researched. The goal of nutrition therapy for the management of type-2 diabetes should focus on promoting healthy eating, stabilizing glucose levels, lowering lipid levels and blood pressure, and promoting weight loss. This needs to be done in a manner that feels achievable by the patient and can be sustainable in the long-term.
In 2013, the American Diabetes Association created a list of recommendations and interventions focused on nutrition therapy which include reduced calorie diet, carbohydrate counting, simplified meal plans, fat intake, healthy food or exchange choices, behavioral strategies, and physical activity. The most recent nutritional guidelines from the ADA conclude that there is no ideal macronutrient ratio for all people suffering from type-2 diabetes and that recommendations need to be individually tailored to each patient’s clinical picture and goal(s). The ADA recommends that patients receive individualized nutrition therapy and work with a nutritionist or registered dietitian specializing in nutrition therapy for diabetes. This new approach has lead researchers to perform studies on the outcomes of several diets. One of the most studied diets has been the Mediterranean diet.
The Mediterranean Diet & Type 2 Diabetes
The Mediterranean diet is rich in functional foods that have active ingredients associated with the management and prevention of diseases like type-2 diabetes. Regular consumption of such functional foods has been associated with reduced cholesterol levels, lower inflammation, and enhanced insulin sensitivity, all factors necessary to prevent and manage type-2 diabetes. The functional foods that are key components of the Mediterranean diet are fruits, vegetables, oily fish, olive oil, tree nuts, and legumes. These foods contain phytochemicals that have been shown to have anti-inflammatory and antioxidant properties as well as beneficial effects on glucose metabolism and the cardiovascular system. It is also interesting to note that exercise seems to enhance the beneficial effect of these functional foods.
Current research also points towards lower carbohydrate diets as being effective for the management of type-2 diabetes. Low carbohydrate diets focus on high vegetable intake, moderate to high protein intake, moderate to high fat intake while restricting the intake of carbohydrates to fruits, whole grains and legumes.
Regardless of the type of diet prescribed, patients suffering from type-2 diabetes should practice calorie deficit through portion control to aid in weight loss which has been proven to be the best tool to manage hemoglobin A1C levels.
How Does Age Affect Risk Factor In The Development of Type 2 Diabetes?
Age is also an important risk factors for the development of diabetes, and one that we must take into consideration when choosing nutrition therapy for type-2 diabetics. While childhood diabetes has reached epidemic proportions in this country, most people diagnosed with type-2 diabetes are diagnosed after the age of 45. Once condition that is associated with age and affects an estimated 43% of men and 26% of women is sarcopenia. Sarcopenia is characterized by a progressive loss of muscle mass and strength at the rate of 3% to 8% per decade. Muscle tissue is an important site for glycogen storage, and it has an important role in glucose metabolism. Therefore, loss of muscle mass negatively impacts glucose management as sarcopenia greatly reduces glycogen storage capacity.
High Protein Diets And Metabolic Disease
Historically, high protein diets have always been feared for patients with metabolic diseases because of the detrimental effect protein could have on kidney function. A recent meta-analysis conducted by Devries et al. indicated that high protein diets (1.5 g per kilogram of body weight) does not negatively impact kidney function on glomerular filtration rate in adults without kidney disease. In the past, it was also thought that excess protein would raise glucose levels through gluconeogenesis process. However, these findings have been discredited by several studies which have proven that gluconeogenesis is a demand- driven process.
New evidence advocates for consumption of higher protein by healthy older adults (1.0-1.2 g/kg/day) to preserve muscle mass and function. Older adults who are malnourished or at risk of malnutrition are recommended even higher amounts (1.2-1.5 g/kg/day). Improving muscle mass and physical performance in older population will directly improve management of type-2 diabetes. One study compared hypocaloric high protein diets versus high carbohydrate diets in older adults with sarcopenia. The researchers found that both diet had similar effects on the total amount of weight lost, but the high protein diet improved insulin sensitivity and preserved lean body mass while the high carbohydrate diet did not. Another study compared a high protein diet with a standard protein diet; the high protein diet induced a greater reduction in fat mass in men and women with type-2 diabetes. While glycemic control improved similarly in all groups, the change in insulin concentration was related to the extent of fat mass lost. This suggests that the higher protein diet may have a more favorable effect on glycemic control than a standard protein diet.
While dietary changes are foundational to the management of type-2 diabetes, behavioral modification cannot be discounted. It is human nature to be resistant to change, and we cannot underestimate the emotional and psychological importance of food. For these reasons, dietary modifications need to be sustainable in the long term. Emphasis needs to be placed on patient education and support so that the new dietary habits are not abandoned at the first obstacle.
Nutritionists and dietitians working with diabetes patients need to work closely with their physicians as well so that medications can be promptly adjusted accordingly. I worked extensively with type-2 diabetes clients, and I am always shocked by the number of people who come to me who are on several medications but do not test their blood sugar regularly. In my practice I do not work with clients who refuse to wear a continuous glucose monitor or refuse to monitor their blood sugar levels several times a day via finger prick.
Weight loss is important for overweight and obese people suffering from type-2 diabetes. Losing weight improves glycemic control and decreases fasting blood sugar concentrations; it can improve insulin action and reduce the need for medication. A meta-analysis of gastric bypass patients showed that more than 2/3 of extremely obese patients with type-2 diabetes who underwent gastric bypass surgery had normalized glycemic control after losing at least 30% of their bodyweight. Patients with severe pancreatic beta cell dysfunction may not be as responsive to weight loss as those with less extensive disease.
Complimentary and Alternative Medicine Treatment of Type 2 Diabetes
Complementary and alternative medicine can be used successfully as adjuvant therapy for the treatment of diabetes. The most common used CAM for type-2 diabetes includes herbal medicine and nutriceuticals, acupuncture, chiropractic adjustments and meditation. Alpha-lipoic acid (ALA) is an antioxidant found in organ meats and dark leafy greens which can lower blood sugar and help prevent or reduce neuropathy. Chromium is a trace mineral found in vegetables and whole grains that helps with glucose metabolism. Cinnamon decreases glucose uptake from the G.I. tract, similar to alpha-glucosidase inhibitors medications. Preliminary studies show that antioxidants found in foods like olive oil, dark chocolate and green tea can lower blood sugar and cholesterol, but more research is needed. Ginseng has been used for hundreds of years by certain cultures as a blood sugar remedy. Practitioners must be cautious when using herbs and supplements in clients who take diabetes medication: always check for drug-herb and drug-nutrient interactions before recommending CAM.
Acupuncture is helpful in reducing the pain associated with peripheral neuropathy. Chiropractic care can help stabilize glucose levels by removing spine misalignment, which ameliorates central nervous system communication and can improve pancreatic function.
Lastly, there is increasing evidence that epigenetics plays a role in the metabolic programming of the fetus. While more research is needed to fully understand epigenetic expression and its relation to the disease, we know that maternal and paternal nutrition can cause genetic dysregulation associated with several components that contribute to type-2 diabetes risk. This might be the reason why children born to mothers affected by gestational diabetes have a higher incidence of type-2 diabetes later in life.
While the medical underpinnings of diabetes are well understood, medications alone cannot reverse type-2 diabetes. Lifestyle and dietary changes should be the primary focus in addressing this metabolic disease. CAM are crucial components in any treatment plan and should have greater prominence in how Western medicine approaches type-2 diabetes.
References:
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Quercetin is a natural plant compound referred to as flavonoid. Flavonoids are a diverse group of phytonutrients that are found in vegetables and fruits. Flavonoids are the natural pigments that give plants their color. Quercetin is found in apples, raspberries, red grapes, cherries, citrus fruits, black tea, and leafy greens. It is particularly high in onions and capers.
Quercetin acts as an anti-inflammatory, and it is especially helpful with joint pain. It has been shown to reduce the risk of metabolic disorders; it can help control blood sugar levels, and it lowers the risk of cardiovascular disease. This phytochemical is also used as adjuvant in the treatment of bladder infection. It helps boost immunity, fight allergies, and even aid exercise performance.
Quercetin Has High Anti-Cancer Potential
Several studies show that quercetin has high anticancer potential. Not only does quercetin have anti-cancer properties, such as cell signaling, growth suppression, but studies show that quercetin can be beneficial also when combined with chemotherapy medication and radiotherapy. Quercetin seems to act on chemosensitization and radiosensitization, but it also protects healthy cells from the side effects of chemotherapy drugs and radiotherapy. Therefore, quercetin may have a beneficial role in anticancer treatment.
Quercetin is also an important antioxidant which facilitates the body’s ability to combat free radicals. Free radicals are unstable molecules that cause cellular damage at high concentrations. These free radicals can lead to severe damage and ultimately chronic illnesses. In animal models, quercetin has been shown to help preserve brain activity in degenerative diseases like Parkinson’s and Alzheimer’s disease.
Ensure That Your Diet Includes Foods That Are High In Quercetin
It is important to get quercetin from the diet, as foods that are high in quercetin are also high in other beneficial nutrients. However, to reach therapeutic doses, this flavonoid is also available as a nutritional supplement in capsule and powder form.
Quercetin is taken orally; the recommended dose is 500mg twice a day for 12 weeks. Taking bromelain and vitamin C can help the body absorb quercetin more efficiently. Some of the side effects include upset stomach, headache, and a tingling sensation in the limbs. While generally considered safe, high doses of quercetin can lead to kidney damage.
References
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Li Y, Yao J, Han C, Yang J, Chaudhry MT, Wang S, et al. Quercetin, inflammation and immunity. Nutrients. 2016 Mar 15;8(3):167.
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