National Diet and Nutrition Survey:
British People aged 19 to 64 years

Methodology

The survey collected information from volunteers whose addresses were identified by random postal sifting and thus in-patients, those in institutional care and those of no fixed abode were excluded.  The following information was collected from participants:

1. a 7-day weighed dietary intake record of all food eaten within and outside the home including alcohol intake
2. blood samples and a 24 hour urine collection for assessment of micronutrient status
3. a record of physical activity, anthropometric measures and blood pressure

Over 5,000 addresses were contacted, 1,724 adults completed the dietary record and 1,347 provided a blood sample.

Main Findings

The report breaks the data down into four age-dependent sub-groups but only total percentages are presented for each sex here. 

Analysis revealed that there was probably some under-reporting of food intakes especially in young men and this may mean that intake data slightly over-represents the percentage of people with poor intakes.

• The amount of energy provided by dietary fats has fallen over the preceding fifteen years to 33% of total energy intake
• Protein intakes were borderline or low  in 2% of men (<45 g/day) and 4% of women (< 35 g/day)
• A low BMI, <18.5 kg/m2 was found in 1% of men and 3% of women.
• Approximately 40% of men and 30% of women exceeded the safe upper weekly limits for alcohol of 21 units and 14 units respectively.
• Anaemia was found in 8% of women and 3% of men and was most commonly but not only due to iron deficiency
• Subnormal serum ferritin levels were found in 11% of women and 4% of men (< 15 ug/l or < 20 ug/l respectively)
• Deficiencies of folate (red cell folate < 350 nmol/l) and vitamin B12 (serum vitamin B12 < 118 pmol/l) occurred in 5% and 3% respectively of adults surveyed but macrocytic anaemia was very rare
• Plasma vitamin C was found to be low (<11.0 umol/l) in 3% of those surveyed
• Plasma retinol levels were low (< 0.7 umol/l) in 1% of all adults
• Plasma retinol levels were mildy elevated (>2.5 - 3.0 umol/l) in 14% of all men and 6% of all women respectively and 7% of women aged 50-64 years had plasma retinol levels > 3.0 umol/l
• Vitamin D deficiency (plasma 25-hydroxyvitamin D < 25.0 nmol/l) was found in 14% of men and 15% of women and was more prevalent in the younger age groups.  There was considerable seasonal variation with blood levels being at their lowest in January to March
• Calcium intakes were below the LRNI in 2% of men and 5% of women
• Potassium intakes were below the LRNI in 6% of men and 19% of women due to the poor intake of fresh fruit and vegetables which averaged approximately 3 servings daily against a target of five or more
• Magnesium intakes were below the LRNI in 9% of men and 13% of women
• Socio-economic deprivation was often the greatest risk factor for nutritional inadequacy
• Nutritional supplements were taken by 29% of men and 40% of women but this only reduced the percentage of those whose intakes were deficient (below the LRNI) by approximately 1% for each nutrient
• Blood mercury levels were also measured and they rose in both sexes with increasing age reaching values above 25.7 nmol/l (>5 ug/l) in over 3% of all adults and were at their highest in women aged 50 – 64 years

Reference:

1.   Henderson L, Gregory J, and Swan G.  The National Diet and Nutrition Survey: adults aged 19 to 64 years.  Volume 1: Types and quantities of foods consumed.  TSO (London 2002).
2.   Henderson L, Gregory J, Irving K and Swan G.  The National Diet and Nutrition Survey: adults aged 19 to 64 years.  Volume 2: Energy, protein, carbohydrate, fat and alcohol intake.  TSO (London 2003)
3.   Henderson L, Irving K, Gregory J, Bates C J, Prentice A, Perks J, Swan G, Farron M.  The National Diet and Nutrition Survey: adults aged 19 to 64 years.  Volume 3: Vitamin and Mineral intake and urinary analytes.  TSO (London 2003)
4.   Ruston D, Hoare J, Henderson L, Gregory J, Bates CJ, Prentice A, Birch M, Swan G and Farron M. The National Diet and Nutrition Survey: adults aged 19 to 64 years.  Volume 4: Nutritional status (anthropometry and blood analytes), blood pressure and physical activity.  TSO (London 2004)