Urban/rural differences in red blood cell fatty acid composition, plasma lipids and diet in Melanesian Fijians.

OBJECTIVE: The aim of the study was to compare red blood cell (RBC) fatty acid composition, plasma lipids and lipoproteins and dietary intake between urban and rural Melanesian Fijians. DESIGN: A cross-sectional study was performed in a random subsample (n = 154) from a total survey population of 589 subjects. SETTING: Melanesian Fijians living in the relatively urban settlement of Nabua, Suva and On the remote island of Qamea (rural) were studied. RESULTS: The proportions of myristic acid (1.4% versus 0.3%, P < 0.001) and arachidonic acid (10.1% versus 11.4%, P < 0.01) were significantly higher and proportions of oleic acid (14.4% versus 13.2%, P < 0.05) and linoleic acid (11.9% versus 8.1%, P < 0.001) were significantly lower in RBC from rural compared with urban men, and a similar pattern was seen in women. Plasma cholesterol levels were significantly (P < 0.05) higher in the rural subjects. Urban/rural differences in plasma cholesterol levels were not significant when the proportion of RBC myristate was taken into account. CONCLUSIONS: The results suggest that consumption of myristic acid from coconut fat is greater and the intake of linoleic acid is less in Fijians living on a remote island and may contribute to their higher plasma cholesterol levels compared with their urban counterparts.

What do middle-aged New Zealanders eat? A dietary survey in 50-54 year olds in south Canterbury and north Otago.

Information on diet was obtained from a random sample of 50-54 year olds in October 1985 when a health survey was conducted in the Timaru health district. This survey formed part of the international cardiovascular diseases and alimentary comparison (CARDIAC) study. A seven-day dietary history was obtained from 99 male and 82 female participants who were not taking any antidiabetic or antihypertensive medication. The median daily energy intake was 10.5 MJ for the men and 6.3 MJ for the women. The median daily total fat intake for men and women respectively was 103 g and 68 g. The median ratio of polyunsaturated to saturated fatty acids was low, 0.19 for the men and 0.18 for the women. Total fat contributed 37.5% to energy intake of men and 38.5% to energy intake of women and alcohol contributed 5.1% for men and 2.1% for women. Mineral and vitamin intakes were generally satisfactory. A substantial proportion of the participants, particularly women, claimed to have decreased their total food, fat, salt, meat, eggs and milk intakes and to have increased their vegetable and fish consumption.

Variations in the mineral concentrations in breast milk during a single nursing, diurnally and on consecutive days.

The concentrations of ionized calcium, total calcium, magnesium, sodium and potassium were measured in breast milk collected from 20 women, 4 to 28 weeks post-partum. No significant differences were found in the mineral concentrations in fore and hind milk. Diurnal variations occurred randomly, with no systematic cyclic changes within the 24-h period and the pattern varied from day to day.

Tea and coffee as sources of some minerals in the New Zealand diet.

Daily intakes of tea and coffee of a representative sample of adult New Zealanders (865 men and 1100 women) were calculated from 24-h dietary recalls. The mineral concentrations in tea and coffee samples were determined by atomic absorption spectrometry and used to estimate daily mineral intakes from these beverages. More than 80% consumed tea and about 60% consumed coffee on the day of the recall. The men drank significantly more tea than the women (p less than 0.001), but coffee intakes were similar. The results indicate that for New Zealand adults tea is a very good source of manganese and it also contains appreciable amounts of potassium. Coffee is a better source of potassium than tea, has appreciable amounts of magnesium, and may contribute significantly to manganese intakes in some instances. The amounts of copper, zinc, sodium, calcium, and iron extracted from tea leaves and coffee beans in the brewing processes are too low to be of any nutritional significance but minerals in the water used in their preparation may make a significant contribution to dietary intakes.

Variability of mineral intakes from drinking water: a possible explanation for the controversy over the relationship of water quality to cardiovascular disease.

The assumption that people using the same water supply have similar intakes of minerals from drinking water is examined. Duplicate samples of all water drunk during a 24 hour period, including that boiled for beverage preparation, were collected by 109 adult subjects. The results showed that there may be more than a tenfold variation in the amount of water people drink daily. In addition it was found that the mineral concentrations in the 24 hour samples can vary markedly from those in water collected from the source or supply or from household taps which are the usual sampling points for epidemiological studies. The convention of using total hardness as an indicator of mineral intakes from hard and soft water is questioned.

Estimations of daily mineral intakes from drinking water.

Duplicate samples of all tap water drank over 24 h, including that used for beverage preparation, were collected from 109 adult subjects. There were more than ten-fold variations in daily water intakes. The mineral concentrations in the 24-h samples from households on the same public water supply showed considerable variation, the differences sometimes being greater than those found in water samples from different sources. These findings raise considerable doubt about the accuracy of accepted methods for the estimation of mineral intakes from drinking water. Although the mineral concentrations in water samples were generally very low some subjects received 10 per cent or more of their recommended dietary intake of Cu and Zn from this source. The implications of the findings are discussed.