The Glycemic Index (GI) is a way of classifying the carbohydratecontent of foods. The Glycemic response is characterised by the effect foods have on blood sugar levels after eating.

The main foods that cause a glycemic response are carbohydrates. Foods that have carbohydrates are:

• breads
• cereals
• grains
• legumes
• rice
• fruits
• vegetables
• high carbohydrate “processed foods”

Carbohydrates were previously classified as either ‘”complex” or “simple”. The GI system replaces this concept.

How the Glycemic Index (GI) works

The GI measures how quickly glucose is released into the bloodstream after eating a particular food and is measured on a scale of 0-100. The slower glucose is released into the bloodstream, the less fluctuations there are in the amount of glucose (or sugar) that is released in the body (consistent and stable blood sugar levels are preferable and promote good health) and the more beneficial the food is.

Foods that have a high GI are broken down into glucose very quickly, so this glucose is released in the bloodstream very quickly. Foods that have a low GI are broken down into glucose very slowly, so glucose is broken down more gradually and the glucose is released more gradually in the bloodstream.

Glucose has a GI of 100 and is used as the base for comparison of the GI of all other foods. For example, a food that releases glucose in the bloodstream at half the rate of pure glucose has a GI of 50.

• Low-GI foods
  These have a GI of 55 or less and include foods such as legumes (lentils, peas, beans, soy), mixed-grain breads, milk, yogurt, most vegetables and most fruits.
• Intermediate GI foods
  These have a GI between 56 and 69 and include foods such as rolled oats, muesli, ice cream, sugar and orange juice.
• High GI foods
  These have a GI of 70 or more and include foods such as white and wholemeal bread, potatoes, rice and honey.

Blood sugar levels of glucose explained

When foods that have carbohydrates in them are eaten, the carbohydrate is eventually broken down into glucose in the digestive system and then the glucose is released into the bloodstream.

Glucose is basically the simplest form of sugar – all carbohydrate foods get broken down into their simplest form in the body – glucose. The body uses glucose for energy in every single cell of the body.

There are two important organs which are involved in the release of glucose in the blood:

• Pancreas – this is the main organ that regulates the amount of glucose that is released in the blood, by secreting a hormonecalled insulin. Insulin is the hormone that allows glucose to enter the cells of the body which gives the cells the energy they require to function properly. The brain requires a lot of glucose energy to function properly
• Liver – this is the organ that stores unused glucose, in the form of glycogen. The liver breaks down glycogen and releases into the blood when the pancreas releases another hormone called glucagon, in response to low levels of glucose in the blood

Fasting blood glucose levels

In order to test for diabetes (or hypoglycaemica) blood glucose levels are taken when a person has been fasting.

• Normal blood glucose: 70mg-100mg per dL
• Prediabetes blood glucose: 110mg-125mg per dL
• Diabetes blood glucose: > 126mg per dL

Glycemic load (GL) explained

The Glycaemic Load (GL) refers to the quantity of a particular food consumed and the blood sugar response in the body to that food.

For example, a 50g serving of a high-GI food (ie watermelon) would produce a slower blood sugar response than 500g of watermelon.

Glycaemic load (GL) is a combination of the quantity and quality of carbohydrate in a food. Foods with the highest GL are high in both GI and carbohydrate content (eg breads, breakfast foods and some fruits and vegetables). Foods with the lowest GL have low GI and low carbohydrate content (eg nuts, fish, cheese, meat). Moderate to low GL foods are preferable to be consumed regularly.

Portion control is also vital in relation to the GL of foods. If a food is low in GI, this does not mean large portions of it should be eaten on a regular basis. This is important to note not just for blood sugar regulation but also for weight control.

Glycemic Index (GI) and Diabetes

Diabetes is a degenerative disease which is basically due to the body’s inability to release or use insulin properly and is associated with blood glucose levels that are too high. There are three types of diabetes:

• Type 1 Diabetes – is caused when the pancreas stops producing any (or much) insulin
• Type 2 Diabetes – is caused when there is an inadequate response to the insulin that is released (insulin resistance)
• Gestational Diabetes – this is a temporary type of diabetes, which affects some women when they are pregnant

Both Types I & Type II Diabetes result in too much glucose remaining in the blood, which causes a variety of symptoms such as frequent urination, continual thirst and tiredness.

People with diabetes are at higher risk for developing serious and deadly heart conditions as well as a range of other serious (and potentially) life-threatening conditions.

A low-GI diet is believed to be helpful to people with diabetes because low-GI foods release glucose into the bloodstream slowly and consistently than high GI foods. Low GI foods deliver carbohydrates more gradually to the bloodstream, without the sudden build-up of glucose that high GI foods produce, leading to hyperglycemia at first, then hypoglycemia when the blood sugar levels drop. Such fluctuations in blood sugar are not beneficial for healthy individuals and are potentially dangerous for diabetics.

Low GI diet and weight loss

Following a low-GI diet does not automatically mean weight will be lost on that diet. The GI only relates to the carbohydrate content of foods and does not take fats, proteins, calories/kilojoules or dietary fibre into consideration. It is important to consider overall calorie intake, as well as fat intake for weight management.

The GI is basically about making smarter carbohydrate choices. In addition to this, smarter fat choices need to be made at the same time by looking at the type of fat in the foods eaten – unsaturate (good) fats vs saturate (bad) fats. It is preferable to have a diet with a moderate amount of good fats and not to limit all fats altogether, as they are necessary for good health.

Since low GI foods take longer to be converted to glucose, they usually give a feeling of being full for longer than high GI foods and so make it less likely to over-indulge.

Low-GI diet vs low-carb diet

Low carbohydrate diets are currently the latest diets in vogue. Some of the low carbohydrate diets, such as the South Beach Diet and the SugarBuster! Diet are based on Glycemic Index. Some of the other low carbohydrate diets, such as the Atkins Diet and Zone Diet are not based on GI, but rather on excluding or limiting certain carbohydrates from the diet.

A low GI diet does not necessarily involve excluding all carbohydrates from the diet but instead is based on selecting foods that have a low GI rating, to enable weight loss and give healthier food choices.

GI labelling in Australia

In Australia, many foods have a GI label on their packaging. It is not mandatory to have a GI label on foods, but because it is the latest “buzz” word, many companies will label their food low GI to appeal to all the people who are on a variety of diets.

When choosing a food based on its GI, it is important to note that GI relates to how quickly glucose is released into the bloodstream. The GI does not specify how much fat, calories or carbohydrate is in the food, so it is not the only indicator for the food’s nutritional benefits. All these factors must be taken into consideration together when choosing foods. In addition to this, if a food is low GI this should not be seen as permission to over-eat that food, as it could be high in calories and/or fat too.

Examples of GI values

The following tables show the GI values of various common foods.

Breads

Breakfast cereals

Fruits

Grains / pasta

Legumes

Vegetables

References

• Glycemic Index, www.glycemicindex.com.au, accessed 5 April 2007
• McGuire M, Beerman KA, Nutritional Sciences: From Fundamentals to Food, 2007 Thomson Wadsworth USA
• Rolfes SR, Pinna K, Whitney E, “Understanding Normal and Clinical Nutrition” 11th Edition,, 2006 Thomson Wadsworth USA

Last reviewed and updated: 27 June 2024

Fibre is the part of plants that cannot be digested and makes up the structure of plants – including fruits, vegetables, grains and legumes.

Fibre is a polysaccharide, which means it is a complex carbohydrate and that is why it is essential for good health. Because of the way that fibre is formed, a lot of it usually cannot be broken down into glucose, so it does not provide much energy to the body – this is insoluble fibre. The other type of fibre does break down and is absorbed by the body – this is soluble fibre.

Most plant foods with a high fibre content also usually have a low GI.

Why fibre is good for you

Fibre has many important healthy benefits:

• Assisting with healthy digestion – fibre is vitally important for good digestion as it helps food move through the digestive tract and specifically through the small intestine and large intestine (colon)
• Lowering cholesterol – fibre is well known to reduce blood cholesterol levels of the LDL (“bad”) cholesterol levels, by binding with the cholesterol molecules and excreting them with the fibre, thus not allowing LDL (“bad”) cholesterol levels to build up in the blood. The following foods are well known to assist in lowering cholesterol – oat bran, fruits, prunes, psyllium, legumes.
• Reducing risk of cancer of the colon – much research has suggested that those individuals whose intake of all types of fibre is high have a lower risk of cancer of the colon, and even have a lower risk of developing polyps of the colon (which usually start as benign lumps, but often become malignant)
• Reducing constipation – a diet which includes insoluble fibre is well known to reduce the incidence of constipation. When insoluble fibre reaches the colon, it has absorbed more water and creates soft, large stools which are easy to pass. Bran and prunes are two foods that are high in insoluble fibre and which are recommended to people who have constipation
• Assisting with diabetes – research has shown that the soluble fibre in certain foods (apples, citrus fruits, pears, legumes, oat bran) slow down the digestion of carbohydrates and so stabilise blood sugar level and glucose metabolism. People with type 2 diabetes often benefit the best from incorporating these foods into their diet

Soluble fibre

Soluble fibre is fibre that will dissolve in water. Soluble fibre is digested in the gastrointestinal tract (usually by the “good” bacteria in the colon) and forms a gel-like consistency when it is dissolved in water.

Foods that are high in soluble fibre:

• Fruits
• Legumes (beans, peas)

Foods that are high in soluble fibre have the following health effects:

• protect against diabetes by lowering blood glucose levels
• protect against heart disease by lowering cholesterol levels

Insoluble fibre

Insoluble fibre is fibre that will not dissolve in water. Insoluble fibre is not readily digested in the gastrointestinal tract.

Foods that are high in insoluble fibre:

• Vegetables
• Grains

Foods that are high in soluble fibre have the following health effects:

• promote regular bowel movements and prevent constipation

Classification of fibre

Fibre is normally classified as being of the following types:

• Cellulose – this is what all vegetables, fruits and legumes have within their cell walls. Cellulose is an insoluble fibre
• Gums & mucilages – gum is the liquid that is secreted from plants when they are cut. Examples of edible gums are – guar gum and gum arabic. Mucilages are the liquid inside plants and are similar in structure to gums. Examples of mucilages are – psyllium and carageen. Both gums and mucilages are types of soluble fibre
• Hemicellulose – cereal fibres are formed mainly from hemicellulose. This is a type of insoluble fibre
• Lignans – lignans are a special type of fibre as they are examples of phytoestrogens, which have eostrogen-like effects on the body. The food with the highest level of lignans is flaxseed. Other food sources are: pumpkin seeds, sesame seeds, rye, soybeans, broccoli, beans, and some berries. Lignans are an insoluble fibre
• Pectins – this type of fibre is what makes up the cells walls of vegetables and fruits (especially citrus fruits and apples). Pectin makes a great gel-like substance when mixed with water and is used extensively in the food industry as a thickener and to control consistency and texture of processed foods. Pectin is a type of soluble fibre
• Resistant starch – while not strictly fibre, some starchy foods are classified with fibre because they are not digested nor absorbed by the gastrointestinal tract (in much the same way as insoluble fibre) – this can be due to a variety of reasons, including the food type and the person’s ability to digest starches properly. Resistant starch can be found in: whole legumes, raw potatoes and unripe bananas

References

• McGuire M, Beerman KA, Nutritional Sciences: From Fundamentals to Food, 2007 Thomson Wadsworth USA
• Rolfes SR, Pinna K, Whitney E, Understanding Normal and Clinical Nutrition 7th Edition, 2006 Thomson Wadsworth USA

Last reviewed and updated: 27 June 2024

Protein is one of the three macronutrients required to be eaten in relatively large amounts each day (the other two are carbohydrates and fats). Protein is basically a whole lot of amino acids joined together in a chain formation. Amino acids are what protein is broken down into, in the digestive system of the body. Amino acids are the building blocks of the body – most parts of the body require protein in order to function properly, and not just the muscles.

Protein serves as a source of energy for the body and to make up various structural components of the body (such as muscle, bones, fingernails, hair and skin).

Protein also has important functional roles in the body – the body uses the protein from foods to create the multitude of protein required in the body. Some of the actions of protein in the body are: to activate enzymes, move skeletal muscles, transportation of various important substance through cell membranes, activate communication of various hormones, provide blood clotting, as well as the regulation of fluid balance and pH.

Protein makes up at least 50% of the human body (that is not made up of water).

Classification of protein

Protein contains various amino acids, which are required to maintain life. There are 20 amino acids that are found in protein. The amino acids come in three forms:

• Essential amino acids – these amino acids cannot be produced by the body (either at all or not enough to be effective) and must be consumed through the diet. There are 9 essential amino acids
• Non-essential amino acids – these amino acids are able to be synthesised from the essential amino acids (and also from glucose) so are not necessary to be consumed through the diet. There are 11 non-essential amino acids
• Conditionally essential amino acids – these amino acids are normally non-essential ones, but they become conditional essential in special circumstances (babies / infants cannot make their own taurine, phyenylketonuria makes the amino acid phenylalanine essential for the individual with this disease as they cannot synthesise it, plus there are other times when some non-essential amino acids may become essential). There are 6 conditionally essential amino acids

Sources of protein

The main source of protein for non-vegetarians is meat and meat products:

• meat
• poultry
• game meat

Non-meat sources of protein are:

• fish
• shellfish
• eggs
• milk
• other dairy
• legumes
• nuts
• seeds

Fruits, vegetables and grains do not contain much protein in comparison to the foods above.

Animal sources of protein usually have higher levels of some essential amino acids than plant sources of amino acids – except for soy (a type of legume), which contains all the essential amino acids. Other legumes (such as dried beans, lentils, peas) and peanuts also have balanced levels of the essential amino acids and are considered a good source of protein, especially for vegetarians.

Protein quality

Protein quality is deemed to be either:

• high quality protein
• low quality protein

The factors that determine whether a protein source is either high or low quality are:

• Digestibility (or bioavailability) – how easily a protein source is digested and absorbed in the gastrointestinal system is one factor
• Essential amino acids – a food source that contains all the essential amino acids in plentiful amounts and at a similar level, is another factor (complete proteins have all essential amino acids in the correct combination and levels, while incomplete proteins do not)

Meat eaters generally eat high quality protein foods, while vegetarians (and especially vegans) need to combine specific foods together in order to get a meal that has high quality protein – while not impossible, it does take extra work and some vegetarians may not be aware of protein quality being a factor in their dietary requirements intake.

The Committee on Dietary Intakes (USA) has developed a way to measure the protein quality in a food. This is determine by measuring the amounts of each amino acid in the food and comparing it against each of the amino acid requirements of pre-school age children.

Complete and incomplete protein

A food high in protein is considered to be a complete protein if it contains all the essential amino acids in high amounts. Foods high in protein, but which do not have adequate amounts of the essential amino acids are considered incomplete protein.

Most meat / fish / eggs and other meat by-products are complete proteins, so most people will get adequate protein and essential amino acids they require, just from eating regular foods. Vegetarians, on the other hand, have a little more work to do in order to get all the protein and essential amino acids they require, as most legumes, beans, nuts, peas are incomplete proteins.

In order to make a complete protein, foods that are incomplete proteins need to be combined and eaten together. This is the way that vegetarians, especially strict vegetarians (vegans), normally get their daily protein requirements.

Why is protein important?

Protein is important because it is broken down into the various amino acids, which are required by the body to produce various essential proteins necessary for the body to function properly. Some of the vital proteins required in the body are: neurotransmitters, blood clotting factors and enzymes. Without protein in the diet, of which the body can absorb the amino acids, and synthesise various proteins, the body would simply not function properly and ill health would ensue.

Protein for vegetarians

Vegetarians need to ensure they get enough high quality protein in their diet from the food they consume.

Soy is the only plant food that is a high quality protein and it may sometimes be difficult (but not impossible) for some strict vegetarians (vegans) to get adequate protein from their dietary intake.

Lacto-ovo and lacto vegetarians (who consume either eggs and dairy or just dairy) have less difficulty in obtaining high quality protein because both milk and eggs in particular are very good high quality protein foods.

Vegetarians (or those who want to adopt a vegetarian diet) would do well to seek the assistance of a dietician to ensure they are consuming adequate amounts of all nutrients and specifically of high quality protein (to ensure they are consuming enough essential amino acids).

References

• McGuire M, Beerman KA, Nutritional Sciences: From Fundamentals to Food, 2007 Thomson Wadsworth USA
• Marieb EM, Hoehn K. Human Anatomy & Physiology. 7th edition, 2006. Benjamin Cummings Publishing
• Rolfes SR, Pinna K, Whitney E, Understanding Normal and Clinical Nutrition 7th Edition, 2006 Thomson Wadsworth USA

Last reviewed and updated: 27 June 2024

Fat is one of the three macronutrients required to be eaten in relatively large amounts each day (the other two are carbohydrates and protein).

Fats and oils are officially known as lipids and they are insoluble in water. The difference between fats and oils is:

• Fats – are solid at room temperature
• Oils are liquid at room temperature

Not all fats are bad. Some fats, such as essential fatty acids, are actually very good for maintaining proper health. The body requires a certain amount of fat each day for good health.

Classification of fat

Fat is a type of nutrient also known as lipids. Lipids include the following types:

• triglycerides (fats and oils) – these come in various forms, both saturated (usually found in animal food sources) and unsaturated (usually found in plant foods) fats. The most preferable type of fat to consume is unsaturated, but small amounts of saturated fat can be tolerated without ill effect, as long as it is part of a healthy, well-balanced diet full of whole foods (wholegrains and natural, unprocessed foods)
• phospholipids – this is the double layer of fat that surrounds all cells in the body and needs to be maintained to keep cells healthy. Phospholipids are also found in various food sources, the most abundant is lecithin
• sterols – found both in plants (phytosterols) and in animal (cholesterol) foods. Sterols are necessary for producing many hormones, vitamin D and for making cholesterol (the body also makes its own cholesterol from other nutrients in the liver)

Triglycides

Triglycerides types of lipids which are formed from three fatty acids attached to a glycerol base.

Triglycerides can be either:

• saturated
• unsaturated

Phospholipids

Apart from the membrane of the cells of the body, the other most common food source of phospholipids is lecithin, which is similar in form to a triglyceride, except that it has 2 fatty acids with a choline molecule, on the glycerol base.

Food sources of lecithin are:

• eggs
• liver
• peanuts
• soy beans
• wheat germ

The liver makes enough of its own lecithin in normally health individuals, but dietary sources of lecithin are still usable.

Phospholipids are useful because they are fat soluble (from the lipid part) and also water soluble (from the phospho or phosphate part), which is a reason why the body cells are permeable to water. Because of their dual properties, phospholipids can help lipids move in and out of cells through the cell membrane.

Sterols

The other type of lipids are sterols, very different to the other two types of lipids. Cholesterol is the most commonly known sterol and it can have both “good” and “bad” effects in the body, and in particular on the cardiovascular system.

Plants contain phytosterols, while animal foods contain cholesterol. Both these types of sterols have healthy effects on the body (except for”bad” (LDL) cholesterol, which needs to be avoided for good cardiovascular health).

The role of sterols are:

• Creation of bile acids – this is essential to help break down fats and absorb their nutrients effectively
• Creation of hormones – the sex hormons in both males and females are synthesised from sterols, as are the adrenal hormones (cortisol and alderosterone)
• Creation of vitamin D – sterols play an important role in manufacturing a type of vitamin D (which is actually classified as a hormone)

Essential fatty acids

Essential fatty acids are those fatty acids that the body cannot manufacture on its own, so are required to be consumed on a daily basis to ensure good health.

The two essential fatty acids (EFAs) are:

• Omega-3 – is derived from linolenic acid. Omega 3 fatty acids are used to make cell walls supple and flexible and improve circulation by ensuring proper red blood cell flexibility and function. Omega-3 deficiency can cause a whole host of health problems – impaired memory, mental problems, tingling in the fingers, reduced immunity, high blood triglycerides and LDL (“bad”) cholesterol levels
• Omega-6 – is derived from linoleic acid. Omega-6 fatty acids have anti-inflammatory properties and are useful for improving skin conditions (eczema), PMS, rheumatoid arthritis and diabetic neuropathy. Omega-6 deficiency is rare, because most people in the West get more than enough of this EFA in their diet

One main function of EFA are to produce prostaglandins, which regulate bodily functions such as:

• heart rate
• blood pressure
• blood clotting
• fertility and conception
• regulate inflammation
• encouraging the body to fight infection

The body requires these two essential fatty acids in a specific ratio to regulate and maintain many functions within the body. The ratio recommended is 4 (Omega 6) : 1 (Omega 3), but in the West, the ratio is more likely to be anywhere from 10:1 to 25:1, which current research shows is not healthy.

References

• McGuire M, Beerman KA, Nutritional Sciences: From Fundamentals to Food, 2007 Thomson Wadsworth USA
• Rolfes SR, Pinna K, Whitney E, Understanding Normal and Clinical Nutrition 7th Edition, 2006 Thomson Wadsworth USA

Last reviewed and updated: 27 June 2024

Carbohydrates are one of the essential nutrients that are necessary for sustaining life and must be supplied to the body (in the form of food that is eaten) each day.

Carbohydrates are nutrients which provide energy.

Carbohydrates are compounds that contain carbon, hydrogen and oxygen molecules arranged in a specific order, depending on whether they are simple or complex carbohydrates.

Carbohydrates are classed as macronutrients as the body requires them in relatively large amounts (in comparison to vitamins, which are micronutrients and less of these are required each day).

Classification of carbohydrates

Carbohydrates used to be classified in terms of being either:

• simple carbohydrates
• complex carbohydrates

These days, the new classification of carbohydrates is called the glycemic index.

Simple carbohydrates

Simple carbohydrates are molecules which the body is able to digest very quckly – they do not need to be broken down too much to be digested and so have a rapid impact on blood sugar levels.

Simple carbohydrates are either:

• Monosaccharides
• Disaccharides

Monosaccharides

Monosaccharides are the simplest types of sugars and can be broken down and absorbed very quickly by the body. They can be of the following three types:

• Glucose – the simplest form of sugar and also know as blood sugar, which is the energy source for all the body’s activities – all cells of the body require glucose in order to function properly. Carbohydrates are generally broken down to glucose in the body, after they are ingested, in order for it to be used for energy
• Fructose – is the sugar that naturally occurs in fruits and in honey (it is also added to canned/bottle drinks, ready-to-eat cereals, ice-cream, desserts, as it is basically the main constituent of “high-fructose corn syrup”). Fructose is the sweetest tasting sugar and gives honey its sweet taste
• Galactose – this rarely occurs naturally and is part of the lactose molecule

Disaccharides

Disaccharides are formed from two joined monosaccharide molecules and are the slightly more complicated than the monosaccharides, but still can be broken down to a simple form and absorbed fairly quickly. They can be of the following three types:

• Sucrose – formed from fructose + glucose. Tastes very sweet because of the fructose. Sucrose is found in:
  • fruits
  • vegetables
  • grains
• Lactose – formed from galactose + glucose. This is found only in:
  • milk
• Maltose – formed from glucose + glucose. Maltose is produced when starch breaks down and during the fermentation process of alcohol. It is found mainly in:
  • barley

Complex carbohydrates

Complex carbohydrates are molecules which the body is able to digest very slowly – they need to be broken down quite a lot in order to be digested and so have a more gradual impact on blood sugar levels.

Complex carbohydrates contain many glucose molecules (polysaccharides) linked together and are:

• Glycogen
• Starch
• Fibre

Glycogen

Glycogen is the name for glucose that is stored in the liver. Glycogen is not considered a significant food source of carbohydrate. The only food that is eaten that contains negligible amounts of glycogen are animal protein foods – but as the amount of glycogen in these foods is negligible, it is not considered a viable way to get this nutrient.

Starch

This type of complex carbohydrate is found in plants. Grains are the richest source of starch. Main types of grains are:

• wheat
• rice
• corn
• millet
• rye
• barley
• oats

Other types of starch are legumes (all types of beans, peas) as well as tubers (potatoes, yams).

Fibre

The structural part of plants are their fibre. Fibre is found in all plant foods:

• fruits
• vegetables
• grains
• legumes

Fibre comes in two types – soluble and insoluble:

• Soluble fibre – this type of fibre dissolves in a liquid and is digested by the body
• Insoluble fibre – this type of fibre does not dissolve and so is not digested by the body

Glycemic Index

Today, the glycemic index and the glycemic load are used to describe the effect that carbohydrates have on blood sugar levels. The article on glycemic index explains this new concept.

Recommended intake of carbohydrates

Latest recommendations for carbohydrates, are that they should consist of about half of the daily calorie intake – which is approximately 45%-65% of the total daily calorie intake.

For example:

An adult on a 2000 calories a day diet needs:

• 225g carbohydrates (if 45% of calorie intake)
• 325g carbohydrates (if 65% of calorie intake)

References

• McGuire M, Beerman KA, Nutritional Sciences: From Fundamentals to Food, 2007 Thomson Wadsworth USA
• Rolfes SR, Pinna K, Whitney E, Understanding Normal and Clinical Nutrition 7th Edition, 2006 Thomson Wadsworth USA

Last reviewed and updated: 27 June 2024