Carbohydrates Past paper questions

Question 1

Differentiate between intrinsic and extrinsic sugars in the diet and provide examples (5)

Answer 1

-Intrinsic sugars are naturally present and built within the cellular structure of foods
-Extrinsic sugars aren’t present and found within the cell structure of foods
-Intrinsic foods include glucose and fructose and extrinsic foods may be found in natural and unprocessed foods such as lactose in milk, or in refined and processed foods such as table sugar and fruit sugars, referred to as FREE SUGARS
-High intakes of extrinsic sugars, apart from lactose, that is NMES, are associated with dental caries, obesity and CVD, whereas there are no evidence of adverse effects from intrinsic sugars

Question 2

Explain the term Glycaemic Index in relation to carbohydrate consumption (5)

Answer 2

-Glycaemic Index is an effective way of ranking carbohydrate containing foods according to the extent they raise a persons blood glucose levels
-Glycaemic Index shows that different carbohydrate containing foods are absorbed and digested at different rates
-A Low GI indicates a slower absorption and digestion rate
-High GI suggests that carbohydrates break down quickly during digestion and release glucose rapidly into the bloodstream

Question 3

Identify the current dietary guidelines for sugar and complex carbohydrates in the diet and consider how following this advice could benefit health (8)

Answer 3

-Free Sugars- 10% of total dietary guidelines
-Complex carbohydrates- increased to 50% of dietary energy

-REDUCED RISK OF DENTAL CARIES- sugars are the main component associated. NMES most commonly associated, complex carbs less degree (due to them having to be broken down before fermentation can occur), Intrinsic (dried fruit and veg) not strongly associated as the sugars are held in the cell wall and not released until chewing breaks down the cell walls

-REDUCED RISK OF TYPE 2 DIABETES- complex carbs (soluble fibre/ NSP) help regulate blood glucose levels whereas a high sugar intake can lead to fluctuations in blood glucose levels

-WEIGHT MANAGEMENT- 1g of carbohydrate foods provide less energy than fat/ protein or alcohol and complex carbs can provide a feeling of satiety, therefore displacing fatty sugary snacks

-REDUCED RISK OF CVD- high blood cholesterol associated with increased CVD risk- NSP binds and traps cholesterol and bile acids and stops then reabsorbing into the bloodstream- reduces cholesterol levels

Question 4

Outline the nutritional benefits of including complex carbohydrates in the diet (5)

Answer 4

-foods, eg potatoes, rice, pasta and bread provide not only complex carbs in the form of starch, but additionally non starch polysaccharides and other nutrients such as protein, iron and b vitamins

-more favourable that high fat foods- lower energy density and higher satiety value- reduces proportions of fat in diet

-some complex carbs (soluble fibre) are more slowly absorbed and can even put blood glucose levels

Question 5

Why reduce free sugars?

Answer 5

-consumption should be no more than 5% of total dietary energy intake

-obesity- low consumption can contribute to a reduction in obesity levels- high NMES are highly palatable, energy dense and stored as fat- also can cause type 2 diabetes (90% of those who are overweight have type 2 diabetes)

-dental health- directly related to dental caries and gum disease- reduction likely to improve this

-blood sugars- NMES raise blood sugar levels very quickly, placing extra demands on insulin and pancreas- a reduction can improve glucose tolerance, help prevent and manage diabetes