9 - Restricted Diets Flashcards
What are restricted diets?
Diets that require a component in the food to be kept within certain limits
What is a calorie restriction (CR) diet?
A diet that restricts calorie intake (most are about 30% less) but adequate essential nutrients
Subjects are normal and without any medical conditions
Found to increase lifespan in rodents, fish, dogs and yeast
Does calorie restriction (CR) result in longevity in humans?
Some studies suggest that CR in primates did not increase longevity. Genes and healthy diet may matter more
Other studies suggest the ratio of macronutrients plays a more important role
Another study suggests that CR increases lifespan but affects the brain
What is the purpose of diet restriction?
Changing eating habits to reduce risk of disease or manage disease
What are some medical conditions that need restricted diets?
Obesity - weight management Cardiovascular diseases - healthy fat diet Diabetes High blood pressure Phenylketonuria (PKU)
How can abdominal fatness be defined?
Using waist to hip ratio (WHR). >1.0 for men, >0.85 for women
What are some obesity-related trends in the Singapore population (18-69y)?
- 8% obese (BMI > 30kg/m^2)
- 1% male, 9.5% female
- 0% Malay, 16.9% Indian, 7.9% Chinese
- 0% are high risk (BMI > 27.5 kg/m^2)
What are the health risks associated with obesity?
Cardiovascular disease Diabetes Atherosclerosis Inflammation Some cancers
What are the causes of obesity?
Increased calories
Genetic susceptibility
Reduced physical activity
What are some weight loss strategies?
Exercise regularly
Small changes to diet (300-500 kcal reduction from usual intake)
Ensure nutrient adequacy by taking foods with high nutrient density but low energy density
Consume lower fat foods (=<30% of total kcal)
Use less cooking oil
Reducing % protein helps reduce fat intake and high energy density foods
Increasing % carbohydrate helps increase fibre and low energy density foods
How to maintain weight loss?
Increase high fiber food - promote satiety, lower energy density, high nutrient density
Increase water intake - increase fullness, help in coping with high fiber diet
Avoid empty calories e.g., sweetened drinks and alcohol
What are some precautions for weight loss strategies?
Do not compromise on nutrient adequacy Diet should be well balanced Nutrient supplements may be required Lower calories should not lead to feelings of starvation - which may lead to irresistible urge Beware of fad diets Beware of weight loss products
Why do weight loss products and services thrive?
Success rate is low in retaining weight loss
Social pressure to maintain normal weight
People are willing to try a quick-fix solution
People believe that if a product sells, it must be effective
Some evidence in animal models
Explanation sounds good
What are cardiovascular diseases, and some examples?
Diseases of heart and blood vessels
Coronary heart disease (CHD) - blood flow to heart affected, leads to heart attack
Stroke - blood supply to brain is affected
> 30% of total deaths in Singapore is due to cardiovascular diseases
What are the functions of LDL and HDL?
LDL transport triglycerides, cholesterol and phospholipid to cells of all tissues
HDL transport cholesterol back to the liver for disposal
What is a healthy fat diet?
For weight loss or maintenance
Reduce LDL level and obtain blood lipid balance
Healthy fat diet:
What is the recommendation for saturated fat intake?
Total fat 20-35% of energy
Limit saturated fat to 7% total energy - taking lower fat food, cut off fats from meat, reduce cream and butter, replace with carbohydrate
Healthy fat diet:
What is the recommendation for cholesterol?
Limit to 200mg
Sources - animal fats
Cholesterol is not essential. Dietary cholesterol has little effect on blood cholesterol
Healthy fat diet:
What is the recommendation for trans fatty acid intake?
Avoid trans fatty acid (small quantities are found naturally in meat and milk)
Healthy fat diet:
What is the recommendation for unsaturated fatty acids intake?
n-6 polyunsaturated fatty acids (linoleic acid) 5-10% energy
n-3 polyunsaturated fatty acids (α-linolenic acid) 0.6-1.2% energy
Approximately 10% of total can come from longer chain n-6 or n-3 fatty acids
Replace meat with fish - low in saturated fat, suppress inflammation, blood clotting, lowering triglyceride levels
What are fat replacers and what are some precautions when using them?
Replace the function of fats in foods (taste, texture and/or cooking properties) with zero or lower calories
Do not contribute to hyperlipidemia (high blood cholesterol)
Can be carbohydrate, protein or fat based
Precaution - fat based fat replacers is able to reduce the absorption of fat soluble vitamin
Avoid deficiency of essential fatty acids
What are some examples of fat replacers?
Fat replacers obtained from food components are GRAS (generally recognised as safe)
- Avicel
- Splendid
- Simplese
- Benefat
Fat replacers which are not natural occurring are tested vigorously for safety before it is approved for use
- Olean - can cause diarrhoea and oily stool if consumed in large quantities
What is type 1 diabetes?
Insulin dependent diabetes mellitus
Damage of pancreatic cells - unable to produce insulin
5-10% of cases
What is type 2 diabetes?
Insulin resistant, not responding to insulin
90-95% of cases
What are the problems associated with diabetes?
Cells suffer from lack of sugar (starvation)
Fat used for energy instead, resulting in ketoacidosis in type 1 diabetes
Insulin in type 2 diabetes inhibit fat breakdown, ketoacidosis is less severe, gluconeogenesis results in dehydration
High blood sugar (hyperglycemia) may affect vision, delay wound healing, heart disease, kidney failure, stroke, loss of limbs etc.
What are the usual body weights of type 1 and 2 diabetics?
Type 1 - normally not overweight
weight gain may be the side effect of insulin treatment
Type 2 - normally overweight
Overweight can worsen insulin resistance
What are some principles of diet management in diabetes?
Balance diet with essential nutrients Maintain ideal weight Meet energy needs Prevent blood sugar variation and keeping it close to normal level Decrease blood lipid levels, if elevated
How can nutrition management in diabetes be achieved?
Consistent carbohydrate content in meals at timed intervals to maintain blood sugar level
Overall calories eaten must be controlled to manage weight over long term
Consumption of carbohydrate must not be lower than 130g per day
Consume low GI foods
Fiber rich foods are encouraged and may improve glycemic control
Healthy fat diet is recommended due to high risk of cardiovascular disease
Protein 15-20% of total
Alcohol - minimise, consume with food to avoid hypoglycemia, may increase triglyceride level
GI does not give extent to which blood glucose is raised by a consumption of a particular amount of a food. What does?
Glycemic load (GL) represents blood-glucose-raising potential of specific amount of food consumed
GL = GI x mass of carbohydrate in food / 100
What are exchange lists for diabetes?
Exchange lists can be set up for each food group
Foods in the same group should have approximately similar number of calories, composition and effects on blood glucose levels
How is blood pressure measured for hypertension?
Systolic (heart beat) pressure/diastolic (heart relax) pressure
Normal - systolic < 120 mmHg, diastolic < 80
Prehypertension - systolic 120-139, diastolic 80-89
Hypertenstion - systolic >= 140, diastolic >= 90
How much sodium is there in 1000mg of salt?
What does excess sodium in hypertension cause?
400mg
Na+ causes dehydration of cell and increase in blood pressure
What is a DASH diet?
Dietary Approaches to Stop Hypertension - people with cardiovascular disease and high blood pressure, reduce asthma symptoms, help with migraine, gastritis and ulcers
Reduce intake of sodium which is related to chronic diseases
How to reduce salt and sodium?
Choose fresh or frozen food, no salt added/rinse salt from food
Choose processed food carefully
Choose low salt versions of soy sauce, teriyaki sauce
Smoked, corned, pickled food may have added salt
Many snack foods also contain added salt
Gluten restricted diet - who is affected, what foods to avoid?
People with celiac sprue
Foods to avoid - all wheat, rye, oats, barley and buckwheat products
Hidden gluten e.g., sausage soy sauce, sauce and gravy mixes
Create an exchange list for each food category
Lactose restricted diet - who is affected, what foods to avoid?
Lactose intolerant
Foods to avoid - foods with lactose, casein, whey, non-fat dry milk solids
Foods containing low level of lactose is possible for the less sensitive e.g., yoghurt, aged-cheese, buttermilk
Caution - lack of Ca2+, can consider adding lactase in milk
