Other British Nutritional Surveys

I - The Dietary and Nutritional Survey of British Adults - 1990

This was the first detailed survey of a representative sample of the British population.  It was conducted between 1986 and 1987 by the Office of Population Census and Surveys with the collaboration of the Department of Health and the Ministry of Agriculture Fisheries and Food.

Its design was very similar to that of the National Diet and Nutrition Surveys which followed on from it.

The sample recruited included 2197 adults aged 16 to 64 years living in private households in Great Britain.  Pregnant women were excluded.  Additionally 76% of respondents provided a blood sample for measurement of various nutrients.

Main Findings

• Obesity as defined by a Body Mass Index, BMI, > 30.0kg/m2 was present in 12% of women and 8% of men.  The figures from a survey conducted in 1980 were 8% and 6% respectively.
• Fat provided 37.6% of total energy intake in men and 39.2% in women with saturated fats providing 15.4% in men and 16.5% in women
• Alcohol provided 6.9% of energy intake in men and 2.8% in women
• A low BMI < 20.0kg/m2 was present in 6% of women and 12% of men.
• Those who reported that they were trying to slim generally had a higher intake than non-slimmers for protein, vitamins and minerals
• Unemployed men and women had lower intakes of vitamins and minerals than those in employment a difference that could not entirely be accounted for by their lower recorded energy intake
• Intakes of many nutrients were lower for informants classified to Social Classes IV and V than for Social Classes I and II.
• With the exception of iron average intakes by all social classes met the RDAs, Recommended Daily Amounts, but there were still significant percentages with a poor intake of some nutrients who also had evidence on testing of various deficiencies
• A low haemoglobin <13.0g/dl was found in approximately 4% of men and < 12.0g/dl in approximately 8% of women
• Evidence of a low iron status was found in 4% of men (<25ug/l) and in 14% of women (<13ug/l) and estimates of low intake (<LRNI) are approximately1% for men and 30% for women
• Folate deficiency, red cell folate < 170 ug/l) was found in 35% of men and 47% of women.  Blood levels correlated with intake and were lower in those from lower socio-economic groups
• Calcium intakes below the LRNI of 400 mg/day were seen in approximately 2% of men and 10% of women
• Vitamin A deficiency (serum retinol<0.7 umol/l) was unknown in men and appeared to be unlikely in women except perhaps a few aged 16-24 years.  However mild excess (>2.79 umol/l) was seen in 13% of men and 5% of women with the prevalence rising with increasing age in both sexes
• The estimated prevalences of low intakes of trace elements (<LRNI) that were seen in a small percentage of both sexes were: copper, men – 0-1%, women – 1-2%; zinc, men – 2%, women – 3%; iodine, men – 0-1%, women – 5%.  No further measures of adequacy/inadequacy were made of these nutrients

References

Gregory J, Foster K, Tyler H, Wiseman M.  The Dietary and Nutritional Survey of British Adults. London: HMSO, 1990.
Ministry of Agriculture Fisheries and Food. The Dietary Survey of British Adults - Further Analysis. London: HMSO, 1994.

II-Low Income Diet and Nutritional Survey: 8 years and over - 2007

The intention of the survey was to examine the diet of the 15% of the British households with the greatest material deprivation.  They were identified by a doorstep questionnaire which assessed household composition, income, car ownership, receipt of benefits and employment status.  Eligible households needed to contain a person aged 8 years or older who had to complete a questionnaire, a four day detailed diet diary and provide a blood sample for analysis.  Where possible, two people, including at least one adult, were surveyed from each eligible household.

Characteristics of Survey Sample
25,818 potentially suitable addresses were identified. 
Adults: 946 men and 1850 women participated with approximately 2/3rds were visited by a nurse and 50% providing a blood sample
Children: 439 boys and 493 girls participated with approximately 2/3rds were visited by a nurse and 12% providing a blood sample.

The authors identified important limitations in the data which need to be borne in mind during interpretation including; small sample sizes in certain sub-groups e.g. for Wales, Scotland and Northern Ireland, for minority ethnic groups and for some age groups, bias in reporting food and drink intakes which may result in under-reporting, however the assessment method for children involved use of a photographic food atlas that may have resulted in over-reporting of intakes.

Main Results

The findings on intake can be compared with those from the comparable age groups from the National Diet and Nutrition Surveys [internal link], which used nationally representative samples that include a proportion of disadvantaged people.  Furthermore comparisons with Dietary Reference Values, in particular assessment of the percentage of the survey sample with intakes below the Lower Reference Nutrient Intake can be made, which would give an idea of the percentage of the population at risk of deficiency.  Finally the findings from blood tests can be compared against standard laboratory norms [internal link] and this gives an idea of the percentage of the population with deficiency (but not a measure of its clinical impact).

In general, the diets of those with a low income were less healthy and less nutritious than those who were less disadvantaged.  The prevalence of deficiency was higher for most but not all nutrients than those who had been surveyed in the National Diet and Nutrition Surveys [internal link] and this was in keeping with expectations.
Specific findings include;
Relatively low intakes of fruit and vegetables in survey participants with adults consuming on average 2.0 portions per day, which is about 25% below the national average. 
The lowest recorded fruit and vegetable intake was in boys age 11 to 18 years who consumed on average 1.5 portions per day, which is even less than their younger counterparts
Energy and protein intakes were on the whole adequate but were estimated to be slightly less than those observed in NDNS
Protein intakes below 35 g per day were observed in % of women and below 45 g per day in % of men.