DIAGNOSIS TEST

DIABETES CAN BE DIAGNOSED BY BLOOD TESTS OR URINE

TESTS

Blood glucose levels Oral glucose tolerance test(OGTT) Glycosylated hemoglobin (Hb A1c%) Glycosuria Benedict's test Ketonuria

Diagnosis of Diabetes

NORMAL IGT or IFG( Impaired Glucose Tolerance or Impaired Fasting Glucose)

DIABETES

FPG (Fasting Plasma Glucose)

>70mg/dl <110 mg/dl

≥ 110 mg/dl & < 126 mg/dl (IFG)

≥ 126 mg/dl

2-h PG (2 hour post load Glucose Test)

< 140 mg/dl ≥ 140 mg/dl & < 200 mg/dl (IGT)

≥ 200 mg/dl &Casual plasma glucose conc. ≥ 200 mg/dl

IMPAIRED GLUCOSE HOMEOSTASIS

IFG (Impaired Fasting Glucose) has been defined as a FPG level of greater than or equal to 110 mg/dl but less than 126 mg/dl.

IGT (Impaired Glucose Tolerance) is defined as an OGTT value of greater than or equal to 140 mg/dl but less than 200 mg/dl.

Both are risk factors for diabetes.

ORAL GLUCOSE TOLERANCE TEST (OGTT)

ORAL GLUCOSE TOLERANCE TEST (OGTT)

OGTT determines the body’s ability to utilize a known amount of carbohydrate.

PROCEDURE: The test is done in the morning after 3 days of

diet containing 150 g of carbohydrate daily with normal activity.

Blood sample is taken to determine the FBG (Fasting Blood Glucose).

75 g of glucose dissolved in 250 to 300 ml of water is then given orally (for children 1.75 g glucose per kg of ideal weight up to maximum of 75 g).

Blood samples are taken at every 30 min for 2 hours, and their glucose level is estimated.

RESULTS OF OGTT

90

45

135

180

225

½ 1 1½ 2

---------------------------------Renal threshold

90

45

135

180

225

½ 1 1½ 2

---------------------------------Renal threshold

mg o

f g

lu /

100 m

l of

blo

od

mg o

f g

lu /

100

ml of

blo

od

Hours Hours

0 0 0 0

0 - Absence of glucose in the urine

+ ++ ++

+ - Presence of glucose in the urine

Normal Curve

Diabetes Mellitus Curve

GLYCOSYLATED HEMOGLOBIN (HBA1C) During the life cycle of RBC’s about 120 days, glucose

molecules attach themselves to Hb to form Glycohemoglobins.

Process of enzymatic attachment of sugar to Hb is called Glycosylation.

Glycosylation indicates a high conc. of glucose over

the life of the cell (4 months). The test shows the average of blood sugar for several months.

Advantage: it is not affected by the short term changes in the blood sugar levels.

GLYCOSYLATED HEMOGLOBIN (HB A1C)

Hb A1c (%) 4 - 7 % : Ideal 7 – 8 % : Satisfactory > 8% : Unsatisfactory

NORMAL MAJOR TYPES OF HEMOGLOBINSTYPES COMPOSITION AND

SYMBOLPERCENTAGE OF TOTAL HEMOGLOBIN

HbA1 Alpha 2 beta2 90%

HbA2 Alpha2 delta2 <5%

HbF Alpha2 gama2 < 2%

HbA1C Alpha2 beta2 glucose

<5%

GLYCOSURIA

GLYCOSURIA : The presence of abnormal amount of

glucose in urine.

PROCEDURE: 2 or 3 hours just before the meal urine is

avoided. Breakfast or lunch is taken with usual

helpings of carbohydrate rich foods such as chapattis, rice, fruits and sweets.

BENEDICT`S TEST

BENEDICT`S TEST

It is the traditional method for detecting reducing substances in urine.

KETONURIA

KETONURIA Presence of ketone bodies in the urine. It can be detected by nitroprusside

reaction which is conveniently carried out using Acetest tabltes or ketostix paper sticks .

If both glycosuria and ketonuria are found, the diagnosis of diabetes is practically cretain.

SOURCES OF BLOOD GLUCOSE

Diet:- most digestible carbohydrates ultimately form glucose and other simple sugars that are transported to the liver via the hepatic portal vein.

Gluconeogenesis:- from gluconeogenic compounds.

Net conversion to glucose without significant recycling e.g. certain amino acids and proprionate.

compounds which are the products of the partial metabolism of glucose in certain tissues and are conveyed to the liver/kidney and re-synthesized to glucose e.g. lactate via Cori cycle.

Glucose is also formed from liver glycogen by glycogenolysis.

BLOOD GLUCOSE LEVEL

The minute-by-minute adjustments that keep the blood glucose level near 4.5 mm involve the integrated actions of several hormones (insulin, glucagon) on metabolic processes in many tissues, primarily liver, muscle, and adipose tissue.

Insulin:- signals that blood glucose concentration is higher than necessary - cells respond by taking up glucose and converting to storage forms.

Glucagon:- signals that blood glucose is too low - cells respond by producing glucose through gluconeogenesis and glycogen breakdown.

If there is not enough glucose in the blood, Glucagon converts some glycogen into glucose.

Glycogen

Glucagon

Glucose in the blood

If there is too much glucose in the blood, Insulin converts some of it to glycogen

Glycogen

Insulin

Glucose in the blood

The glucose in the blood increases.

Glycogen

Insulin

Glucose in the blood

But there is no insulin to convert it into glycogen.

Glucose concentration rises to dangerous levels.

HORMONES THAT AFFECT BLOOD GLUCOSE

Insulin:- Insulin plays a central role in regulating blood

glucose concentration. It is produced by the cells of the Islets of

Langerhans in the pancreas, as a direct response to the degree of hyperglycemia.

It is a heterodimeric polypeptide consisting of two chains linked by disulfide bridges.

It is synthesized as pre-proinsulin, stored in secretory granules as proinsulin, and released as mature insulin.

Time

Glucose Concentration

Meal eaten

Insulin is produced and glucose levels fall to normal again.

Glucose levels rise after a meal.

Normal

GLYCEMIC INDEX

GLYCEMIC INDEX (GI)

A GI value tells only how rapidly a particular carbohydrate turns into sugar.

The incremental area under the blood glucose curve (AUC) after the ingestion of 50 gram of a test food, expressed as a percentage of the AUC of an equal amount of a reference food (generally glucose or white bread)

Blood glucose response to 50 g test food GI = --------------------------------------------------------------x 100

Blood glucose response to 50 g reference food

• The calculated GI values are then categorized as low, medium and high; the numerical value that is representative of these categories depends on the reference food used (i.e. white bread or glucose).

• Glycemic Index Categories:-LOW GI = 55 or lessMEDIUM GI = 56 to 69HIGH GI = 70 or more

FACTORS AFFECTING GLYCEMIC INDEX

TYPE OF STARCH:- contains two types of molecules : amylopectin & amylase

Amylase:- 20-30% Amylopectin:- 70-80%

Amylase absorbs less water, the molecules form tight clumps which slows the rate of ingestion.

Kidney beans have higher levels of amylase that is GI:-28.

Amylopectin absorbs more water and they are more open and lead to a higher rate of digestion.

Gluttonous rice have higher amylopectin that is GI:- 98

PHYSICAL ENTRAPMENT:-It is the way food is encased and the ability of the food to be absorbed by the body & it is also effect the GI ranking. Eg. bran has a physical barrier which slows down the enzymatic activity of the internal starch layer during digestion. Bran has low GI:-38.

VISCOSITY OF FIBER:- viscosity is the measurement of the thickness of the liquid.

A high viscosity item has a sticky consistency somewhere between liquid & a solid.

This can have large influence of foods GI ranking as viscous soluble fiber can transform the contents of the intestine into a gel like matter.

A slower rate of digestion reduces the rate of rise in blood glucose levels.

SUGAR CONTENT:- sugar content of food item also affects its ranking. Food with higher sugar content are more likely to be ranked higher as sugar is a food item very similar to glucose.

FAT AND PROTEIN CONTENT:- slow the gastric emptying( the process by which food exists the stomach & enters the duodenum) The duodenum aids digestion by secreting enzymes into the material passing down from the stomach.

By slowing down gastric emptying the food matter is absorbed more slowly by the body which reduces blood glucose levels.

COOKING:- the cooking process swells the starch molecules in food and softens it. This speeds up the rate of digestion giving rise to higher levels of blood glucose.

GLYCEMIC LOAD

GLYCEMIC LOAD GL is a ranking system for CHO content in

food portions based on their GI & the portion size.

Actually GL is the total amount of CHO contained in each food, food preparation or meal.

The usefulness of GL is based on the idea that a high glycemic index food consumed in small quantities would give the same effect as larger quantities of a low GI food on blood sugar.

GL= GI valueX CHOper serving/100

EXAMPLES OF GI & GL OF SOME FOODS (FOSTER-POWELL ET AL., 2002)PRODUCT GI(GLUCOSE=100) CARBOHYDRATE

(g/100g)GL(g/100g)

Glucose 100 100 100

Corn flakes 81 86 70

White bread 70 47 33

Porridge 58 9 5

Coca cola 58 10 6

Rice, long grain 56 27 15

Mango 51 14 7

Whole grain bread 51 43 22

peach 42 10 4

Apple juice 40 10 4

Apple 38 13 5

yogurt 36 6 2

RELATION OF GLYCEMIC INDEX AND DIABETES

GI is food ranking system that gives lower number to foods that result in lower and more gradual blood glucose increases, & a higher number to foods that raise blood levels more drastically and more quickly. A particular food has ranking within the GI the total GL depend on the serving size together with the amount of CHO that serving.

ARTIFICIAL SWEETNERS

ARTIFICIAL SWEETNERS An ideal sweetener is as or sweeter than

sucrose, has a pleasant taste with no after taste, is colorless, readily soluble, stable, functional and economically feasible.

It is nontoxic does not promote dental cavities and is either metabolized normally or excreted from the body unchanged without contributing to any metabolic abnormalities.

When multiple sweetener are used together they have a synergistic effect.

LOW CALORIE SWEETENER

POLYOLS: Polyols occur in nature, they are synthesized on industrial scale from easily accessible CHO such as starch, sucrose, glucose, invert sugar, xylose, and lactose.

Sugar alcohols(xylitol, sorbitol, mannitol, maltitol lactitol, isomalt) Known as polyols are white crystalline, slightly hygroscopic, water soluble powders.

They are less sweet and 50% of energy of polyols is available to human body.

Average caloric value is 2.4kcal/g. Polyols are suitable for diabetics because rapid glycemic response is avoided.

For the same reason sorbitol & xylitol are often included in parenteral nutrition to provide more controllable CHO energy source to glucose or fructose.

Due to induced digestibility of polyols, their intake should be restricted to 40-50g/day for adults & 30g /day for children in order to avoid gastrointestinal discomfort.

NON CALORIE SWEETENER

CYCLAMATE. It is 30 times sweeter than sucrose.It taste much like sugar & is heat stable.It was banned following a report that some rats receiving very large doses had developed tumors of the urinary bladder.

Acelsulfame –k. It is a synthetic derivative of aceto-acetic acid. It is not metabolized in the body & is excreated unchanged.

It has little undesirable after taste.At very high concentrations it exhibits lingering bitter & metallic flavor attributes.

Acelsulfame-k, the potassium salt of acelsulfame is up to 200 times sweeter than a 3% sucrose solution.

In mixtures of acelsulfame-k & aspartame there is a strong synergistic enhancement of sweetness.

Blends are 300 times sweeter than sucrose solutions while individually they are only 100 times sweeter.

ALITAME. It is a dipeptide based amide & has a sweet taste similar to sugar. It is more than 2000times sweeter than sucrose.

Aspartame. It is made by combining two amino acids:-aspartic acid & phenylalanine- & adding methyl alcohol to form a methyl ester.

Aspartame is a white, odourless, crystalline powder that has a sugar like taste and instability to sweetness potency 180-200 times that of sucrose without any bitter aftertaste.

Since it can not be utilized by the body the caloric value is insignificant.

It is not stable to heat & changes chemically & loses sweetness.

Its heating can be corrected by encapsulating a core of granulated aspartame with a water resistant coating of polymer or a layer of fat.

After the outer layer melts, the core layer slowly hydrates ,releasing the aspartame in the final stage of baking.

SACCHARIN:- it is sodium ortho benzene sulphonamide or the calcium salt.

It is stable in a wide variety of products under extreme processing condition.

It can be synthesized with relatively few impurities and is inexpensive.

It gives bitter after taste at higher concentration.

When used in combination with aspartame or cyclamate , sweetness is enhanced &bitterness is decreased.

SUCROLOSE:- white crystalline solid produced by the selective addition of chlorine atoms to sucrose.

It is 600 times sweeter than sugar & no bitter after taste. It is very soluble in water & stable at high temperatures and therefore can be used in baked goods.

Sucrolose does not interact with any other food components.