- Carbohydrates Universidad National Autónoma de México
- Selection of nutrients and other components Food and Agriculture Organization
- Carbohydrates College of Charleston
- Dietary carbohydrates: sugars and starches US Department of Agriculture
- Calculation of the energy content of foods – energy conversion factors Food and Agriculture Organization
- Carbohydrates: Clinical effects of inadequate intake The National Academic Press
- Dietary Reference Intakes: Macronutrients US Department of Agriculture
- List of foods high and low in carbohydrates US Department of Agriculture
- List of foods high and low in available carbohydrates Fineli.fi
- Christian M et al, 1999, Starch digestion in infancy Journal of Pediatric Gastroenterology and Nutrition
- Buchman Al et al, 2004, The Medical and Surgical Management of Short Bowel Syndrome Medscape
- Trehalose Health Canada
- Achten J et al, 2007, Exogenous Oxidation of Isomaltulose Is Lower than That of Sucrose during Exercise in Men PubMed
- Hamada S et al, 2002, Role of sweeteners in the etiology and prevention of dental caries International Union of Pure and Applied Chemistry
- Dietary Guidelines for Americans, Carbohydrates Health.gov
- Latulippe ME et al, 2011, Fructose Malabsorption and Intolerance: Effects of Fructose with and without Simultaneous Glucose IngestionTaylor Franscis Online
- Skoog SM et al, 2008, Comparison of breath testing with fructose and high fructose corn syrups in health and IBS PubMed Central
- Myers VH et al, 2007, Nutritional effects on blood pressure PubMed
- Jakobsen MU et al, 2009, Major types of dietary fat and risk of coronary heart disease: A pooled analysis of 11 cohort studiesNutritionEvidenceLibrary.gov
- 2015 Dietary Guidelines Advisory Committee, What is the relationship between intake of saturated fat and risk of cardiovascular disease?Health.gov
- Cook GC et al, 1981, Jejunal absorption rates of glucose and glycine in post-infective tropical malabsorption
- Ojetti V et al, 2009, Small bowel bacterial overgrowth and type 1 diabetes European Review for Medical and Pharmacological Sciences
- Levy RG et al, 2012, Ketogenic diet and other dietary treatments for epilepsy PubMed
- Ko DY et al, Epilepsy and Seizures Treatment & ManagementEmedicine
- Lefevre F et al, 2000, Ketogenic diet for the treatment of refractory epilepsy in children: A systematic review of efficacy PubMed
- Keene DL et al, 2006, A systematic review of the use of the ketogenic diet in childhood epilepsy PubMed
- Hoyt CS 3rd et al, 1977, Low-carbohydrate diet optic neuropathyPubMed
- Quiroz-Kendall E et al,1983, Acute variegate porphyria following a Scarsdale Gourmet Diet PubMed
- Poh-Fitzpatrick MB, Variegate porphyria treatment & managementEmedicine
- Veggiotti P et al, 2010, Glucose transporter type 1 deficiency: ketogenic diet in three patients with atypical phenotype PubMed
- Wang D et al, 2002, Glucose Transporter Type 1 Deficiency SyndromeGene Reviews
- Kodama S et al, 2009, Influence of Fat and Carbohydrate Proportions on the Metabolic Profile in Patients With Type 2 Diabetes: A Meta-Analysis PubMed Central
- Sluijs I et al, 2010, Carbohydrate quantity and quality and risk of type 2 diabetes in the European Prospective Investigation into Cancer and Nutrition–Netherlands (EPIC-NL) study The American Journal of Clinical Nutrition
- Jentjens RLPG et al, 2003, Oxidation of exogenous glucose, sucrose, and maltose during prolonged cycling exercise Journal of Applied Physiology
- Gannon MC et al, 2006, Control of blood glucose in type 2 diabetes without weight loss by modification of diet composition Nutrition & Metabolism
- Foster-Powell K et al, 2002, International table of glycemic index and glycemic load values: 2002 The American Journal of Clinical Nutrition
- Glycemic Index The University of Sydney
- Janssens JP et al, 1999, Effects of soft drink and table beer consumption on insulin response in normal teenagers and carbohydrate drink in youngsters PubMed
- Carbohydrates and blood sugar Harvard T.H. Chan
- Goff LM et al, 2013, Low glycaemic index diets and blood lipids: a systematic review and meta-analysis of randomised controlled trialsPubMed
- Nutrition Recommendations and Interventions for Diabetes–2006, A position statement of the American Diabetes Association Diabetes Care
- Brand-Miller J et al, 2006, Low–Glycemic Index Diets in the Management of Diabetes A meta-analysis of randomized controlled trials
- Livesey G et al, 2008, Glycemic response and health—a systematic review and meta-analysis: relations between dietary glycemic properties and health outcomes The American Journal of Clinical Nutrition
- Lattimer JM et al, 2010, Effects of Dietary Fiber and Its Components on Metabolic Health PubMed Central
- Barclay AW et al, 2008, Glycemic index, glycemic load, and chronic disease risk–a meta-analysis of observational studies PubMed
- Brand JC et al, 1991, Low-Glycemic Index Foods Improve Long-Term Glycemic Control in NIDDM Diabetic Care
- Fontvieille AM et al, 1992, The use of low glycaemic index foods improves metabolic control of diabetic patients over five weeksPubMed
- Liljeberg H et al, 2000, Effects of a low-glycaemic index spaghetti meal on glucose tolerance and lipaemia at a subsequent meal in healthy subjects PubMed
- Ajala O et al, 2013, Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes PubMed
- Castañeda-Gonzáles LM et al, 2011, Effects of low carbohydrate diets on weight and glycemic control among type 2 diabetes individuals: a systemic review of RCT greater than 12 weeks PubMed
- Malik VS et al, 2010, Sugar-Sweetened Beverages and Risk of Metabolic Syndrome and Type 2 Diabetes PubMed Central
- Greenwood DC et al, 2013, Glycemic index, glycemic load, carbohydrates, and type 2 diabetes: systematic review and dose-response meta-analysis of prospective studies PubMed
- Wang Q et al, 2015, Effects comparison between low glycemic index diets and high glycemic index diets on HbA1c and fructosamine for patients with diabetes: A systematic review and meta-analysis PubMed
- Tmoas D et al, 2009, Low glycaemic index, or low glycaemic load, diets for diabetes mellitus Cochrane
- Ooi CP et al, 2011, There is insufficient evidence for the use of carbohydrates to improve cognitive performance in older adults with normal or mild cognitive impairment Cochrane
- Bravata DM et al, 2003, Efficacy and safety of low-carbohydrate diets: a systematic review PubMed
- Clifton PM et al, 2014, Long term weight maintenance after advice to consume low carbohydrate, higher protein diets–a systematic review and meta analysis PubMed
- Hession M et al, 2009, Systematic review of randomized controlled trials of low-carbohydrate vs. low-fat/low-calorie diets in the management of obesity and its comorbidities PubMed
- Stellingwerff T et al, 2014, Systematic review: Carbohydrate supplementation on exercise performance or capacity of varying durations PubMed
- Naude CE et al, 2014, Low carbohydrate versus isoenergetic balanced diets for reducing weight and cardiovascular risk: a systematic review and meta-analysis PubMed
- Siri-Tarino PW et al, 2010, Saturated Fatty Acids and Risk of Coronary Heart Disease: Modulation by Replacement Nutrients PubMed Central
- Colombani PC et al, 2013, Carbohydrates and exercise performance in non-fasted athletes: A systematic review of studies mimicking real-lifePubMed Central
- Berglund L et al, 2012, Evaluation and Treatment of Hypertriglyceridemia: An Endocrine Society Clinical Practice GuidelinePubMed Central
- Hu T et al, 2012, Effects of low-carbohydrate diets versus low-fat diets on metabolic risk factors: a meta-analysis of randomized controlled clinical trials PubMed
- Santos FL et al, 2012, Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors PubMed
- de Munster JS et al, 2007, Whole grain, bran, and germ intake and risk of type 2 diabetes: a prospective cohort study and systematic review PubMed
- Chanson-Rolle A et al, 2015, Systematic Review and Meta-Analysis of Human Studies to Support a Quantitative Recommendation for Whole Grain Intake in Relation to Type 2 Diabetes PubMed
- Maghsoudi Z et al, 2015, Empirically derived dietary patterns and incident type 2 diabetes mellitus: a systematic review and meta-analysis on prospective observational studies PubMed
- He FJ et al, 2006, Fruit and vegetable consumption and stroke: Meta-analysis of cohort studies NutritionEvidenceLibrary.gov
- Foroughi M et al, 2013, Stroke and Nutrition: A Review of StudiesPubMed Central
- Sherzai A et al, 2012, Stroke, food groups, and dietary patterns: a systematic review PubMed
- Dietary Guidelines for Americans, Selected Food Groups (Fruits and Vegetables, Whole Grains, and Milk Products) Health.gov
- Does cooked food contain less nutrition? Beyond Vegetarism
- Kelly SAM et al, 2007, Wholegrain cereals for coronary heart disease Cochrane
- Nielsen JV et al, 2006, Low-carbohydrate diet in type 2 diabetes. Stable improvement of bodyweight and glycemic control during 22 months follow-up PubMed Central
- Gross LS et al, 2004, Increased consumption of refined carbohydrates and the epidemic of type 2 diabetes in the United States: an ecologic assessment The American Journal of Clinical Nutrition
- 2011, Low-carbohydrate diets for peole with type 2 diabetes Diabetes UK
- Ajala O et al, 2013, Systematic review and meta-analysis of different dietary approaches to the management of type 2 diabetes The American Journal of Clinical Nutrition
- Select Committee on GRAS Substances (SCOGS) Opinion: Arrowroot Starch U.S. Food and Drug Administration
What are carbohydrates?
Carbohydrates are organic compounds that contain carbon, hydrogen and oxygen in the ratio 1:2:1. Carbohydrates were once considered carbon hydrates (carbon substances containing water), which is now known to be untrue, but the term has persisted. According to a modern definition, carbohydrates are polyhydroxic aldehydes or ketones, which are substances with hydroxy (OH) and aldehyde (CHO) or ketone (C=O) functional groups . Most carbohydrates consist of one or more sugar molecules, such as glucose or fructose .
Chart 1 reference: FAO.org 
Are carbohydrates essential nutrients?
To date, no carbohydrate deficiency is known, so carbohydrates are not considered essential nutrients . Theoretically, you can survive without consuming any carbohydrates, because they can be produced in your body from fats and proteins .
Population studies in Alaska and Greenland have revealed no apparent detrimental effects of a lifelong very low carbohydrate diets on health or longevity . In one 1928 study, Caucasians tolerated carbohydrate-free diet for one year “quite well” .
Even if not essential nutrients, carbohydrates are an important part of healthy diets.
Functions of Carbohydrates in the Human Body
The two main functions of the dietary carbohydrates are to provide[3,4,5]:
- Energy (about 4 kilocalories or 17 kilojoules per gram)
- Building blocks, mainly carbon atoms, for the synthesis of glycogen, fatty acids, amino acids and other substances in your body.
Chart 2. Recommended Daily Intake of Carbohydrates
|Acceptable Macronutrient Distribution Range (AMDR) – the acceptable percent of calories that come from carbohydrates — is 45-65%.||Diet||Carbohydrates (grams)|
|1,000 Cal diet (2-year old)||110-160 g|
|1,500 Cal diet (10-year old)||170-245 g|
|2,000 Cal diet (sedentary adult women)||225-325 g|
|2,500 Cal diet (sedentary adult men)||280-405 g|
|Recommended Dietary Allowance (RDA) – the minimum daily amount of carbohydrates used by the brain||All age groups, except infants||130 g|
|Adequate Intake (AI) — the amount of carbohydrates that should suffice for the brain needs for carbohydrates for up to 98% of infants.||Infants 0-6 months||60 g|
|7-12 months||95 g|
Reference: IOM  NOTE: The amounts of carbohydrates presented above are not “required amounts” but the amounts which the Institute of Medicine in the U.S. recommends as part of a balanced diet. Lower or greater amounts of carbohydrates are not, by themselves, unhealthy.
Plant and Animal Carbohydrates
Plant carbohydrates include glucose, fructose, galactose, mannose,sucrose, maltose, trehalose, sugar alcohols (mannitol, sorbitol, xylitol),starch, cellulose, hemicelluloses, galactomannans, glucomannans and various other polysaccharides found in gums and seaweeds.
Sugars in honey (fructose, glucose, sucrose, isomaltulose) can be considered either plant- or animal-derived.
Carbohydrates in human milk include lactose and human milk oligosaccharides (HMO).
Carbohydrates can be semi-synthetically produced from naturally occurring carbohydrates, such as glucose, lactose or wheat or–in the United States–from cornstarch, by using enzymes and/or certain chemicals. Semi-synthetic carbohydrates may be used as artificial sweeteners, food additives, added fiber, prebiotic supplements, or binders in pills.
A. Semi-synthetic carbohydrates obtained by treating plant carbohydrates:
- Semi-synthetic sugars: altrose, arabinose, corn syrup, dextrose (D-glucose), erythrose, erythrulose, fucose, gulose, idose, high corn fructose syrup (HFCS), invert sugar, isomaltulose, lyxose, rhamnose, ribose, ribulose, sorbose, tagatose, talose, threose, trehalose, xylose (wood sugar), xylulose.
- Semi-synthetic sugar alcohols or polyols: erythritol, hydrogenated starch hydrolyzates (HSH) or polyglucitol, isomalt, lactitol, maltitol,mannitol, sorbitol, xylitol
- Semi-synthetic oligosaccharides: fructooligosaccharides (FOS), gluco-oligosaccharides, isomalto-oligosaccharides, lactosucrose, maltotriose,mannan oligosaccharides, N-acetylchitooligosaccharides, oligodextrose, oligosaccharides from melibiose, pectic oligosaccharides, xylooligosaccharides.
- Semi-synthetic polysaccharides: carboxymethycellulose, dextrin, gellan gum, inulin, maltodextrin, methylcellulose, microcrystalline cellulose,modified food starches, partially hydrolyzed guar gum (PHGG), polydextrose, pyrodextrins, xanthan gum.
B. Semi-synthetic carbohydrates obtained by treating animal carbohydrates:
- Galactooligosaccharides (GOS) obtained from lactose
- Chitosan obtained from chitin (from crab shells)
C. Glycerin(e) or glycerol can be derived either from plant oils or animal fats ad can be added to commercial animal or plant foods.
- The main source of carbohydrates in the human diet are plant foods, such as cereals, root vegetables (potatoes, yams, cassava), fruits and legumes (beans, peas, lentils) and table sugar .
- Animal sources of dietary carbohydrates are milk (lactose), animal liver and seafood (glycogen).
- The main carbohydrate in human breast milk is lactose.
- Carbohydrates, mainly sugars and fibers, can be added to foods, such as fruit juices, jams, soft drinks, energy drinks, liqueurs, dairy products, sweets and sauces.
Chart 3. Foods High in Carbohydrates
|FOOD (serving)||AVAILABLE CARBOHYDRATES (total carbohydrates minus fiber) (grams)|
|Mango chutney (1 cup, 250 g)||90|
|Chestnuts, European (1 cup, 143 g)||70|
|Apple pie (1 piece, 120 g)||55|
|Cookies, fortune (2 oz, 57 g)||50|
|Rice, white, cooked (1 cup, 158 g)||45|
|Raisins, seedless (2 oz, 57 g)||40|
|Macaroni, cooked (1 cup, 140 g)||40|
|Granola bar, soft, plain (2 oz, 57 g)||35|
|Soft drinks (12 oz, 355 mL)||Up to 35|
|Cake, chocolate (1/8 of 18″ cake, 64 g)||35|
|Doughnut, chocolate coated (large, 3-1/2″ dia, 67 g)||35|
|Pizza, thick crust, pepperoni (1 slice, 106 g)||30|
|Potato, boiled (1 cup, 156 g)||30|
|Figs, dried (2 oz, 57 g)||30|
|Fruit juice (1 cup, 240 mL)||Up to 30|
|Candies, hard (1 oz, 28 g)||25|
|Ready-to-eat cereals, dry (3/4 cup, 30 g)||25|
|Coffee liqueur (1 jigger, 1.5 oz, 45 mL)||25|
|Cornmeal, polenta, prepared (1 cup, 160 g)||20|
|Bread, wheat (2 slices, 50 g)||20|
|Apple (1 medium, 3″ dia, 182 g)||20|
|Ice cream, vanilla, soft (1 cone, 100 g)||20|
|Human breast milk (1 cup, 240 mL)||15|
|Honey (1 tbsp, 21 g)||15|
|Oatmeal, regular, prepared (1 cup, 160 g)||15|
|Corn syrup, dark (1 tbsp, 20 g)||15|
|Chocolate, milk (1 oz, 28 g)||15|
|Kidney beans (1/2 cup, 88 g)||15|
|Jam, fruit, average (1 tbsp, 20 g)||15|
|Wine, desert, sweet (3.5 fl oz, 100 mL)||15|
|Beer (12 fl. oz, 355 mL)||~13|
|Milk, whole, 3.2% fat (1 cup, 240 mL)||13|
|Pistachios, dry roasted (2 oz, 57 g)||10|
Chart 3. references: USDA , Fineli.fi 
Available and Unavailable Carbohydrates
Available carbohydrates or “net carbs” are part of carbohydrates that can be completely absorbed in the small intestine and can provide about 4 Calories per gram. Available carbohydrates include:
- Sugars: glucose, fructose, galactose, mannose, sucrose, lactose, maltose, isomaltose, isomaltulose and trehalose
- Starch, dextrin and maltodextrin
- Glycerol (glycerin)
To calculate available carbohydrates from the Nutrition Facts labels, distract dietary fiber from total carbohydrates.
Partially available carbohydrates, such as tagatose and sugar alcohols or polyols (sorbitol, xylitol, etc.), are partially absorbed in the small intestine and partially fermented by colonic bacteria into short-chain fatty acids and other nutrients that can be absorbed and can provide 1.5-3.5 kilocalories per gram.
Unavailable carbohydrates cannot be digested and absorbed in the small intestine. They include:
- Soluble fiber, such as fructooligosaccharides (FOS), galactosaccharides (GOS), galactomannans, glucomannans and resistant starches. Soluble fiber can be broken down (fermented) by the large intestinal bacteria into short-chain fatty acids, which can be absorbed and can provide about 2 Calories per gram.
- Insoluble fiber, such as cellulose, cannot be digested and also not fermented by the large intestinal bacteria so it does not provide calories.
Starch is partially broken down to a disaccharide maltose in the mouth by the enzyme salivary amylase, and further in the small intestine by pancreatic amylase–delivered by a pancreatic juice–into dextrins, maltotriose, maltose and isomaltose, which are further broken down by the enzymes maltase and isomaltase to glucose . NOTE: Raw starch is digested slowly and incompletely [73,79].
Disaccharides are broken down to monosaccharides with the help of the enzymes in the intestinal lining: sucrose is broken down to glucose and fructose by sucrase, lactose to glucose and galactose by lactase, maltose to two glucoses by maltase, and trehalose to two glucoses by trehalase.
Monosaccharides glucose, fructose, galactose, mannose, and glycerin(e)/glycerol can be directly absorbed in the small intestine without being previously digested by enzymes. A semi-synthesized sugar tagatose, and sugar alcohols (lactitol, maltitol, mannitol, sorbitol, xylitol) can be only partly absorbed in the small intestine; the rest of them are broken down (fermented) by the large intestinal bacteria to smaller molecules that are partly absorbed.
Oligosaccharides, such as fructooligosaccharides (FOS), and dietary fiber, such as cellulose, pectin and gums, cannot be digested by the enzymes in the small intestine, but can be at least partially broken down (fermented) by beneficial large intestinal bacteria to short chain fatty acids (SCFA), monosaccharides, hydrogen, methane, or carbon dioxide, which can be partially or completely absorbed.
Nondigestible carbohydrates can be a significant source of energy for individuals whose small intestine has been partly removed (short bowel syndrome or SBS) .
Prebiotics are indigestible carbohydrates that selectively promote the growth of the beneficial large intestinal bacteria. Prebiotics include fructooligosaccharides, trans-galactooligosaccharides, inulin, lactulose and resistant starches.
FODMAPs (Fermentable Oligo-, Di- and Monosaccharides And Polyols) are slowly digestible or indigestible carbohydrates that may cause abdominal bloating in some people, especially in those with irritable bowel syndrome (IBS).
Chart 4. Carbohydrate Digestive Enzymes (Glucosidases)
|ENZYME||SOURCE||SITE of ACTION||FUNCTION|
|Salivary alpha-amylase||Salivary glands, mother’s breast milk glands||Mouth||Splits cooked starch and glycogen (at alpha 1-4 bonds) to dextrins, isomaltose and maltose|
|Pancreatic alpha-amylase ||Pancreas||Duodenum||Splits cooked and uncooked starch and glycogen (at alpha 1-4 bonds) to dextrins, isomaltose and maltose|
|Glucoamylase ||Small intestinal mucosal cells||Small intestinal lining||Splits starch (at alpha 1-6 bonds) to smaller carbohydrates and cleaves glucose molecules, one by one, from starch (at alpha 1-4 bonds)|
|Sucrase||Small intestinal mucosal cells||Small intestinal lining||Splits sucrose to glucose and fructose|
|Lactase||Small intestinal mucosal cells||Small intestinal lining||Splits lactose to glucose and galactose|
|Maltase (alpha-glucosidase)||Small intestinal mucosal cells||Small intestinal lining||Splits maltose to two glucose molecules|
|Isomaltase (dextrinase)||Small intestinal mucosal cells||Small intestinal lining||Splits isomaltose to two glucose molecules; splits isomaltulose and trehalulose to glucose and fructose; splits starch (at alpha 1-6 bonds) to dextrins|
|Trehalase ||Small intestinal mucosal cells||Small intestinal lining||Splits trehalose to two glucose molecules|
There is an absorption limit for various carbohydrates:
- It seems that in healthy individuals only up to 60 grams of glucose per hour can be absorbed .
- Healthy individuals can absorb only about 20-50 grams of fructose from one meal, when fructose is the only carbohydrate in the meal; the presence of glucose increases the absorption rate of fructose [16,17].
Carbohydrate digestion and subsequent absorption of glucose, fructose and galactose can be impaired in viral gastroenteritis (stomach flu), food poisoning, celiac disease, Crohn’s disease, advanced chronic pancreatitis, tropical sprue , small intestinal bacterial overgrowth (SIBO), intestinal parasites, intestinal lymphoma, cystic fibrosis, after partial surgical removal of the stomach resulting in dumping syndrome or removal of the small intestine resulting in short bowel syndrome (SBS).
Glycemic Index (GI) and Glycemic Load (GL)
Glycemic response is the effect of the dietary carbohydrates on blood glucose levels . Glucose and other carbohydrates that are broken down to only glucose during digestion (starch, maltodextrin, maltose) tend to raise blood glucose levels after meals more than fructose, sucrose, galactose and lactose . Glycemic response depends on the glycemic index of the food, amount of ingested carbohydrates, individual differences in glucose absorption and eventual presence of diabetes mellitus .
Glycemic index (GI) is a measure of the effect of carbohydrate foods on the blood glucose levels . Foods with a high glycemic index trigger rapid and high increase of blood glucose levels. The reference food is glucose, which has glycemic index 100 .
- Examples of foods with low GI (55 or below): most fruits and vegetables, whole-grain breads and pasta, legumes/pulses, unsweetened dairy products, products extremely low in carbohydrates (some cheeses, nuts) or high in fructose
- Grains with GI 55-70: Pasta al-dente, parboiled rice, whole-grain bread and very high-fiber cereals.
- Examples of foods with high GI (70 or above): white rice, white bread, corn flakes, baked potatoes, watermelon, croissants, extruded breakfast cereals and sugar-sweetened soft drinks [37,38].
- Glycemic index and glycemic load of common foods
- A search tool for glycemic index and glycemic load
Glycemic load (GL) is a product of glycemic index (expressed as a percentage) and amount of digestible carbohydrates in a meal. GL = GI/100 x available carbohydrates in grams (available carbohydrates = total carbohydrates – dietary fiber) .
GL <10 is considered low and GL>20 is considered high . Glycemic index and glycemic load values of foods are of a limited value in predicting blood glucose spikes, since blood glucose responses to foods may vary greatly within individuals, among individuals and with food characteristics . For example, glycemic index of a given food may increase with ripeness, food processing and cooking time and decrease with co-ingestion of fats, proteins or insoluble fiber (whole grains).
Low-Carbohydrate (Ketogenic) Diet
There is SOME EVIDENCE that a low-carbohydrate diet can be effective in:
- Better control of seizures in children with epilepsy that does not respond to regular drugs; however, the low-carb diet is often poorly tolerated long-term [23,24]
- Glucose transporter type 1 deficiency syndrome (GLUT1 DS) [30,69]
There is INSUFFICIENT EVIDENCE about the effectiveness of a low-carbohydrate diet in the prevention or treatment of diabetes mellitus type 2 [75,77,78], heart disease [60,65], high blood pressure [18,65], high cholesterol , or in promoting weight loss [56,57,58,60,64,65].
Possible harms of a low-carbohydrate diet
- Individuals on a very low-carbohydrate diet who do not consume any fruits and vegetables are at risk of developing vitamin deficiencies, such as vitamin B1 (thiamin) deficiency, which can result in a damage of the optic nerve and visual loss .
- One systematic review mentions that 16 children with epilepsy died during the low-carbohydrate diet , but it is not known, if the low-carbohydrate diet itself has contributed to deaths.
- Low-carbohydrate or other unbalanced diet may trigger symptoms in individuals with variegate porphyria [28,29].
There is SOME EVIDENCE that consumption of 3 or more servings ofwhole grains and/or fruits and vegetables is associated with decreased risk of diabetes type 2 [34,66,67,68,72] and stroke [69,70,71]. NOTE: The health benefits of whole grains, fruits and vegetables may be associated either with dietary fiber or other non-carbohydrate nutrients or both.
Total carbohydrate intake does not seem to be associated with the risk of developing diabetes 2 [44,72], but a diet that is high in carbohydrates and with high glycemic index may be [33,76].
A diet high in carbohydrates (sugars and starch, but not sugar alcohols) may increase the risk of dental caries , but there is INSUFFICIENT EVIDENCE if replacing sugars with non-sugar artificial sweeteners reduces the risk .
There is INSUFFICIENT EVIDENCE about the effectiveness of any type of carbohydrates in improving cognitive performance in older individuals . and of diets high in whole grains in the prevention of coronary heart disease [72,74].
Carbohydrates and Blood Lipids (Cholesterol, Triglycerides)
There is SOME EVIDENCE that diets with low glycemic index can:
- Lower LDL cholesterol and do not affect HDL cholesterol and triglyceride levels .
There is STRONG EVIDENCE that replacing saturated fats with carbohydrates lowers blood total and LDL cholesterol but also lowers HDL cholesterol and increases triglycerides [20,32,61,63] and does not seem to decrease the risk of coronary heart disease .
Carbohydrates and Diabetes
There is SOME EVIDENCE that:
- High total carbohydrate intake is not associated with the risk of developing diabetes 2 or high blood glucose or insulin levels or HbA1c values [15,44].
- High consumption of sugar-sweetened beverages (soft drinks, fruit drinks, iced tea, energy drinks and vitamin water drinks) is associated with increased risk of diabetes 2 .
- Low-glycemic index diets are associated with lower HbA1c values in individuals with diabetes type 2 [42,46,47,48,49,53,54]
There is INSUFFICIENT EVIDENCE about the preventative effect of low-carbohydrate  or low-glycemic [15,41,45,52] diets on the risk of developing diabetes type 2.
Carbohydrates and Physical Performance
The type and amount of carbohydrates and their ability to be absorbed and oxidized does not seem to have any effect on the physical performance in exercises lasting less than 1 hour [59,62].
In exercises lasting more than 2 hours, carbohydrates intake improves physical performance mainly by increasing the carbohydrate oxidation rate .
- Hydrogenated starch hydrolysates (HSH)
- Fructo-oligosaccharides (FOS)
- Galacto-oligosaccharides (GOS)
- Human milk oligosaccharides (HMO)
- Isomalto-oligosaccharides (IMO)
- Mannan oligosaccharides (MOS)
- Raffinose, stachyose, verbascose
- SOLUBLE FIBER:
- Acacia (arabic) gum
- Beta mannan
- Carageenan gum
- Carob or locust bean gum
- Fenugreek gum
- Gellan gum
- Glucomannan or konjac gum
- Guar gum
- Karaya gum
- Psyllium husk mucilage
- Resistant starches
- Tara gum
- Tragacanth gum
- Xanthan gum
- INSOLUBLE FIBER:
- Chitin and chitosan
- Aspartic acid
- Glutamic acid
- FATTY ACIDS
- Alpha-linolenic acid (ALA)
- Eicosapentaenoic (EPA) and Docosahexaenoic acid (DHA)
- Arachidonic acid (AA)
- Linoleic acid
- Conjugated linoleic acid (CLA)
- Short-chain fatty acids (SCFAs)
- Medium-chain fatty acids (MCFAs)
- Long-chain fatty acids (LCFAs)
- Very long-chain fatty acids (VLCFAs)
- Vitamin A - Retinol and retinal
- Vitamin B1 - Thiamine
- Vitamin B2 - Riboflavin
- Vitamin B3 - Niacin
- Vitamin B5 - Pantothenic acid
- Vitamin B6 - Pyridoxine
- Vitamin B7 - Biotin
- Vitamin B9 - Folic acid
- Vitamin B12 - Cobalamin
- Vitamin C - Ascorbic acid
- Vitamin D - Ergocalciferol and cholecalciferol
- Vitamin E - Tocopherol
- Vitamin K - Phylloquinone
- Flavanols: Proanthocyanidins
- Flavanones: Hesperidin
- Flavonols: Quercetin
- Flavones: Diosmin, Luteolin
- Isoflavones: daidzein, genistein
- Caffeic acid
- Chlorogenic acid
- Tannic acid
- Alcohol chemical and physical properties
- Alcoholic beverages types (beer, wine, spirits)
- Denatured alcohol
- Alcohol absorption, metabolism, elimination
- Alcohol and body temperature
- Alcohol and the skin
- Alcohol, appetite and digestion
- Neurological effects of alcohol
- Alcohol, hormones and neurotransmitters
- Alcohol and pain
- Alcohol, blood pressure, heart disease and stroke
- Women, pregnancy, children and alcohol
- Alcohol tolerance
- Alcohol, blood glucose and diabetes
- Alcohol intolerance, allergy and headache
- Alcohol and psychological disorders
- Alcohol and vitamin, mineral and protein deficiency
- Alcohol-drug interactions
- Moderate, heavy, binge drinking
- Alcohol intoxication
- Alcohol poisoning
- Alcohol and gastrointestinal tract
- Alcoholic liver disease
- Long-term effects of excessive alcohol drinking
- Alcohol craving and alcoholism
- Alcohol withdrawal