The digestibility of the starch in plant foods is highly variable, and is dependent on a number of factors, including the physical structure of both the starch and the food matrix. An in vitro technique has been developed to categorize starch in plant foods according to its likely rate and extent of digestion in the human small intestine. The in vitro method provides values for rapidly digestible starch, slowly digestible starch and resistant starch (RS). In the present study values for the RS content of foods, as measured by the analytical technique, were compared with the recovery of starch from these foods when fed to healthy ileostomates. Nine ileostomy subjects were given a polysaccharide-free diet with a breakfast supplement, on each of 2 d (two subjects) or 3 d (seven subjects), of biscuits made from wheat, potato or banana flours or from moist-heat-processed wheat or maize flours. RS intakes measured in vifro ranged from 8·5 to 15·0 g/d for the test biscuits, and mean starch recoveries in ileostomy effluent were 100·4 (n5, range 91−106)% of those values, but there was substantial variation between individuals. It is proposed that RS is defined as ‘the sum of starch and starch-degradation products that, on average, reach the human large intestine’. The analytical method for the measurement of RS in vitro based on this definition is shown to provide an accurate prediction of the average amount of starch that is likely to escape complete digestion and absorption in the human small intestine.

The glycaemic index (GI) is an in vivo measurement based on the glycaemicresponse to carbohydrate-containing foods, and allows foods to be ranked on the basis of the rate of digestion and absorption of the carbohydrates that they contain. GI values are normalizedto a reference amount of available carbohydrate and do not reflect the amounts of carbohydrate normally present in foods; for example, a food with a low content of carbohydrates will have a high GI value if that carbohydrate is digested and absorbed rapidly in the human small intestine. This is potentially confusing for a person wishing to control his or her blood glucoselevels by the choice of foods. The rate and extent of starch digestion in vitro has been measured using a technique that classifies starch into three major fractions: rapidly digestible starch (RDS), slowly digestible starch (SDS) and resistant starch (RS). In addition, thistechnique gives a value for rapidly available glucose (RAG), which includes RDS, free glucose and the glucose moiety of sucrose. When the values for thirty-nine foods were expressed on the basis ofthe available carbohydrate content of these foods, highly significant (P<0·001) positive correlations were observed between GI and both RDS and RAG. The measurement of RAGin vitro provides values for direct calculation of the amount of glucose likely to be rapidly absorbed in the human small intestine and,thus, to influence blood glucose and insulin levels. These values can be used to compare foods, as eaten,on an equal-weight basis. Food-table RAG values would allow simple calculation of the total amount of RAG provided by single foods, by whole meals and by whole diets. Studies are planned in which RAG and the glycaemic response in man will be measured for identical food products.

Dietary intakes of starch and non-starch polysaccharides (NSP) have been estimated for a rural West African community. These people eat directly from shared bowls of cooked food, and so measurement of any individual's food intake is not possible. Recently developed methodology for estimating food intake under these circumstances and the analysis of samples for dietary polysaccharides are combined to yield estimates of intakes of about 375 g starch and 25 g NSP/d for adult males, with lower intakes for women and children, related to their smaller body weights. These intakes are not direct measurements but are extremely plausible when compared with values obtained for other societies where the complication of the shared food bowl does not impinge upon the measurements.

Novel methodology is described for the estimation of food intake in the particularly difficult circumstance where groups of people eat directly from a shared bowl of cooked food. Detailed observation and measurement of meal preparation is combined with food table values for composition to calculate the nutrient content of each meal. The distribution of food between individuals is estimated by a suitable algorithm. The ability of the algorithm to identify seasonal changes in energy intakes is demonstrated by comparison of the calculated energy intakes with values for the total energy expenditure of free-living adult male subjects, as measured by the stable isotope, doubly-labelled water technique. This comparison suggests that the energy intake calculated from detailed observation of two cooked meals per day is equivalent to approximately 80% of the total energy expenditure and, by inference, total dietary energy intake. The remaining energy intake may well be derived from uncooked ‘snack foods’, such as raw fruit and vegetables, or from cooked food obtained, by purchase or as a gift, away from the home. This is the first description of a successful method for the estimation of food intake when people eat directly from shared bowls of food.

The Ca and P intakes of 148 pregnant and lactating women in a rural village in The Gambia. West Africa, have been estimated by direct weighing of food on a total of 4188 d. The Ca and P contents of local foods were determined by analysis of raw ingredients, snack foods and prepared dishes. Information about the contribution of mineral-rich seasonings was obtained. Efforts were made to discover unusual sources of Ca that might not be perceived as food by subject or observer. The main contributors to daily Ca intake were shown to be leaves, fish, cereals, groundnuts and local salt. Cow's milk accounted for only 5 % of Ca intake. Unusual sources of Ca were discovered, namely baobab (Adansonia digitata) fruit and selected earths, but these were consumed infrequently and their contributions to Ca intakes were small. Cereals and groundnuts were the main sources of P. Ca and P intakes (mg/d) were shown to average 404 (SD 110) and 887 (SD 219) respectively. Seasonal changes in the availability of leaves, cereals and groundnuts resulted in variations in Ca and P intakes. The rainy season was associated with increased Ca intakes (by 16%) but decreased P consumption (by 15%). No difference was observed in Ca intake between pregnant and lactating women but P intake in lactation was 11 % higher than that in pregnancy during the post-harvest season. The implications of these low Ca intakes require investigation.

Most (98%) of the fat in human milk is present as triglycerides. This paper describes the use of a clarification procedure that enables the level of human milk fat to be determined by measurement of glycerol released by enzymic hydrolysis of triglycerides. The method requires only 10–50 μl milk, thus presenting a possible technique for work with small mammals, and is suitable for use with autoanalysers, permitting rapid sample throughput.

It is impossible to estimate exactly what weight should be given to each of the various factors which have contributed to the conflict between the Communist regimes of Russia and of China, but there can be no doubt that Russia's refusal to assist China to become a nuclear power was one of the most important. According to the Chinese account of the matter, the Soviet Union promised to provide China with “a sample of an atomic bomb and technical data concerning its manufacture,” apparently as part of an agreement on “new technology for national defence” concluded in October 1957, but went back on this promise and unilaterally annulled the agreement in June 1959. The Chinese People's Republic, nevertheless, went ahead on its own and exploded its first atomic bomb on 16 October 1964; this was followed by China's first hydrogen bomb on 17 June 1967.

If the shade of a Ch'ing mandarin who had been alive in October 1864—just after the collapse of the T'ai'ping rebellion—had attended the celebrations this year of the fifteenth anniversary of the foundation of the Chinese People's Republic, he would have found much that was strange to him, but also a great deal that was familiar and many things of which he could approve. He would learn that, as in his own time, the empire had been reunited after a period of civil war, and he would further note with satisfaction that the vigorous new dynasty which now held the Mandate of Heaven had established the authority of the central government to a degree which in his time he had never known. He would find that with the exception of those tiresome people, the Khalkha Mongols, who had apparently succeeded in breaking away from the empire with the aid of the Tsar of Russia, almost all the territory which in his recollection had been held by the Ch'ing was now subject to an unprecedently firm administration from Peking. He would also observe that the position of the imperial government in relation to foreign states had greatly improved. His own memory would go back to the capture of Peking by the British and French armies in 1860, the hurried departure of the Court of Jehol to escape from the invasion of the barbarians, and the humiliating treaties which had to be concluded with them because of their irresistible weapons.