Dietary patterns Flashcards
What are four CVD facts?
- Affects about 7 million in the UK
- More than 1/4 deaths in England
- > 15% total disability adjusted life years in England
- More vulnerable for higher deprived using index of multiple deprivation
What are general CVD risk factors?
Age, gender, obesity, diet, smoking, inactive excessive alcohol, hypertension, high cholesterol levels, diabetes, dyslipidaemia, insulin
What are specific diet risk factors?
- Higher dietary fat, especially trans and sat fat (increases atherosclerosis risk)
- Increased sodium (increases hypertension risk)
- Low WG, F&V, nuts and seeds, omega 3, polyunsaturated FA, fibre
What effect does fruit and vegetables and dietary fibre have against CVD?
A protective effect
What happens when you increase saturated fat intake from meat?
increased LDL (bad) cholesterol
What does research between red meat and CVD show?
Contrasting results, difference between processed meat and read meat due to saturated fat and cholesterol amounts
What was the largest contribution to the population level CVD mortality burden (both sexes - European CVD stats 2017)
Dietary risk factors
What does dietary patterns look at?
Specific nutrients/foods and their related disease outcomes
What is the dietary patterns approach definition?
Qualities, quantities, proportions, variety or combinations of different foods and beverages in diets, and the timing, location, frequency with which they are habitually consumed
What are the advantages of dietary patterns?
- More comprehensive representation of dietary intake (foods, not isolated nutrients)
- Incorporates some of the complexity of food intake
- Captures aspects of dietary behaviour and food choice
What is the public health perspective of dietary patterns?
It is advantages to be able to identify subpopulations with particular dietary patterns to provide informed dietary recommendations, tailored interventions and monitor changes in patterns
How are dietary patterns measured?
Not directly
What are three methods of assessing dietary patterns?
- Index/score
- Data-driven methods
- Specified dietary patterns
What is the index/score method?
- Uses priori (before data collection) index/score selected at the start
- Scoring system is based on dietary recommendations
- Selected individuals are scored by comparing diet to index/score system
- Externally imposed structure, i.e. index based
What are examples of index/scoring methods?
- Mediterranean diet score
- Healthy eating index
- DASH score
What are the two types of data driven methods?
- Cluster analysis
- Factor analysis
What is cluster analysis?
- Consider dietary intakes then determine groups of people with district patterns e.g. food diary
- Groups are mutually exclusive and relatively homogenous
- Groups are described/defined in terms of the dietary pattern they hold e.g. western diet
What is factor analysis?
- Consider dietary intakes and then determine foods that are correlated and track together to explain differences in intake across patterns
- Based on dietary intake, elements of diet are identified
- Relationships between dietary patterns and health outcomes examined
What are specified diets?
- Categorise individuals based on having specified diets or not
- Consider intakes and preferences of individuals
- Typically based on self-reported patterns, not dietary assessment and on what foods are excluded e.g. vegan, pescatarian
Summarise the dietary patterns methods?
- Selective diets is people who meet/don’t meet criteria
- Index/scores is individual scores on quality and its components
- Cluster analysis: groups of individuals and diet patterns
- Factor analysis: factors explaining variation in individual scores
Define the Mediterranean diet?
- High intake of fruit and vegetables, nuts, legumes, wholegrain, olive oil, fish, cheese/yogurt, monounsaturated and saturated FA
- Reduced intake of meat, meat products, dairy
Define the Western diet?
- Increased fat, protein, salt, processed food, fast food, red meat, butter, high fat dairy products, eggs, added sugar, refined grains
- Low intake of fruit & vegetables, wholegrain, fibre
Define prudent diet?
- Higher fruit and vegetables, legumes, wholegrain, fish, other seafood
What are the disadvantages of dietary patterns?
- Methods e.g. food diary, introduce bias and error
- Dietary patterns not universally or specifically defined by researchers, no specific number or specification
What to be aware of when considering evidence between studies?
- Studies may have the same dietary pattern but different definitions
- Participant treatments may differ e.g. support or not, food provided by researcher or not
- Different scoring methods and versions of scores, dietary patterns may be population specific
What was the New American Plague?
CHD
When was the Seven Countries Study carried out and by who?
1950s/60s
Pett et al
How many participants in the SCS?
1200 healthy middle aged men in many countries (7)
What was the objective of the SCS?
Explore association of diet and lifestyle and disease rates between populations and among individuals, particularly looking at CHD
What risk factors were identified as affecting heart attack rates/longevity of participants?
Smoking, blood pressure and high cholesterol
How were meats, fish and dairy products used?
As condiments rather than focus of the meal
What did the SCS find?
about 10 fold difference in incidence heart disease and mortality between Mediterranean diet and north Europe diet
What else did the study find?
Documented a correlation between saturated fat intake and CVD
Why is defining MeDiet problematic?
- Broad geographical area
- Variations in relevant aspects e.g. cultural, religions, agriculture
What was different about the initial studies?
The population had increased olive oil, fish, meat, wile greens and physical activity, but decreased energy intake. Also partly Greek Orthodox Christians e.g. fasting/not eating meat, dairy etc
How is MeDiet characterised? (Ros et al)
- High olive oil
- High plant foods
- Frequent but moderate wine (esp. red) with meal
- Moderate consumption of fish, seafood, yogurt, cheese, poultry and eggs
- Low red, processed meat and sweets
What are suggestions to upgrade MeDiet?
- Change from common olive oil to extra virgin
- More nuts, fatty fish and wholegrain cereal
- Less sodium intake
What is the main study for CVD and Mediterranean?
PREDIMED
What is PREDIMED?
Landmark study (gold standard with nutrition and health outcomes) assessed long term effects of MeDiet on CVD in men and women at high risk
What kind of trial is PREDIMED?
Randomised control trial