Nutritional Assessments of 3-Day Dietary Records in National Institute for Longevity Sciences-Longitudinal Study of Aging ( NILS-LSA )

Food and nutrient intake of NILS-LSA participants 40 to 79 years of age were assessed through 3-day weighed dietary records by gender and age. The results were as follows. The intake of fats and oils, meats and beverages tended to decrease, but fruits increased with age in both males and females. Regarding nutrient intake, energy, protein, fat, and cholesterol showed a decrease as individuals aged. The nutrient intake in the 70 to 79 yr group was significantly lower than other age groups of both genders. The total dietary fiber and vitamin C intake increased. Salt intake exceeded 10g/day in every group. The percentage of energy from fat to total energy was higher than 25% in most age groups. The proportion of fatty acids was almost appropriate in all groups. J Epidemiol, 2000 ; 10 : S70-S76.


INTRODUCTION
The National Institute for Longevity Science -Longitudinal Study of Aging (NILS-LSA) started in 1997.The NILS-LSA assesses the aging process by epidemiological studies.It is said that many of the physiological and pathological changes associated with aging have important relationships with nutrition.There are many questions about the role of nutrition in the aging process 1.3).Therefore, a series of studies on nutrition as well as medical, physical, psychological, and social problems has been conducted in the NILS-LSA.
In the nutrition survey, many methods have been devoted for measuring the common dietary intake4,5).The dietary record (DR) has been one of the most reliable methods for nutritional assessment.Because the subjects were requested to weigh all food items before cooking them, the amount of macro and micronutrition should be relatively accurate.For this reason, the DR are often regarded as the "golden standard" for investigating food intake.In Japan, 3-day dietary records (3DR) had been adopted in the national nutrition survey (NNS) for a long time.However, the DR method is limited by the fact that individual food intake is highly varied from day to day.No method

Subjects
Between November 1997 and March 1999, 1,130 people in the neighborhood of the National Institute for Longevity Sciences center participated in the NILS-LSA.After excluding those without 3DR data, 1,038 subjects (531 males and 507 females, 40 to 79 years of age) underwent an analysis of food and nutrient intake.

Dietary Assessments
The 3DR was carried out on three continuous days (two weekdays and one weekend day).The food was weighed separately with a scale before being cooked or the portion sizes were estimated.The subjects took photos of the dishes before and after eating with a disposable camera.Dietitians used the photos to complete the data, and telephoned to resolve any discrepancies or to obtain further information when necessary.After completion, the records were reviewed and coded.Food was divided into 18 groups and the averages of the three day food and nutrient intakes were calculated according to the fourth edition of the Standard Tables of Foods Composition in Japan 9) and other sources 10-16) The substituted food composition table for Japanese food developed by Sasaki et    For females, energy, protein, fat, TFA, and cholesterol in the 70 to 79 yr group were significantly lower than in other age groups.The nutrients which showed a decreasing or increasing trend were fewer than in males.
The percentage of energy from protein, fat, and carbohydrate to total energy is shown in Figure 1.The percentage of energy from fat in females was higher than in males.The percentage of energy from fat decreased with age; it was more than 25% in younger age groups.
The proportion of fatty acid is shown in Figure 2. The average proportion of saturated fatty acid to monounsaturated fatty acid to polyunsaturated fatty acid was 31:39:30.There was not a huge difference among age and gender groups.

DISCUSSION
In the NILS-LSA, the intake of some foods or some nutrients showed a significant age difference.The National Nutrition Survey (NNS) has been conducted to obtain data on citizens' health condition, food and nutrient intake, and to clarify relations between nutrition and health in Japan 19).Regarding the NNS in 1997 9,20), the intake of cereals, potatoes and starches, beans, fruits, and green vegetables increased with age.While the intake of fats and oils, milk and dairy food, meats and prepared foods decreased, the intake of energy, protein, and fat in the 70 to 79 yr group also decreased more than in other age groups.The NILS-LSA showed a similar age trend with the intake of nutrients to the NNS, but the intake of nuts and seeds, eggs and milk and dairy food was higher than in the NNS among every age group.As for longevity studies of aging, the Koganei study is one of the most famous in Japan 21,22).The intake of green vegetables, fruits and milk and dairy food were higher in the cross-sectional data of the Koganei study in 1991 than in the NNS in 1996 23).From the first half of the

National Health and Nutrition Examination
Surveys III (NHANESs III), Phase 1 (1988Phase 1 ( -1991)), which was conducted in the U.S., the intake of energy, protein , fat, and cholesterol decreased with age, especially, the intake of energy decreased remarkably 20,24) For health reasons, it is important to assess the adequacy of nutrient intake compared to the Recommended Dietary Allowance (RDA).Some vitamins and minerals might be consumed less than the RDA in the USA 8,20,25,) or in other countries 2627).In Japan, the intake of vitamins is almost at the level of the RDA, fifth edition 28), but the intake of calcium was still below the RDA 28), and iron intake of younger and premenopausal females is still insufficient.There is a serious concern regarding an increase of osteoporosis in a society composed largely of elderly people.Calcium intake is thought to be associated with bone mineral density, and sufficient calcium intake might reduce osteoporosis 2, 20).In the NILS-LSA, the calcium intake in the 40 to 49 yr group was still below the RDA 2$1, but other groups were above the RDA 28).As for iron intake in the NILS-LSA, it was almost above the RDA 28) except in the 40 to 49 and 50 to 59 yr groups for females.In the Koganei Study, the intake of calcium and iron was almost satisfactory.
As for salt intake, an excess intake of salt is one of the risk factors of hypertension, which is a cause of cerebrovascular disease 21,9).The intake of salt in the NILS-LSA was higher than the RDA for every age gender group.Salt intake in the NNS in 1997 19) was also higher than the RDA 28), suggesting that salt intake for Japanese exceeded more than lOg/day.There were marked dietary changes during the period of high economic growth in Japan.During this period, the increase in fat consumption was the most significant among the major nutrients.The NNS in 1997 19) warned that the excessive intake of fat was associated with lifestyle-related disorders, such as obesity, hyperlipidemia, coronary heart disease and cancer 2, 3,20,28,).The proportion of energy from fat to total energy was higher than 25% in many age groups in the NILS-LSA.It exceeded more than 28%, especially in young age groups.Regarding the NNS in 1997 19), the proportion of energy from carbohydrate to total energy trended to increase with age, but fat to total energy decreased.The tolerable upper level of fat intake by the RDA M is 25%.Fat intake in the 20 to 29, in NILS-LSA  30 to 39, and 40 to 49 yr groups exceeded the 25% level.In addition, a high intake of saturated fatty acid and cholesterol and a low intake of polyunsaturated fatty acid increased the level of serum cholesterol 19), which can lead to coronary heart disease and stoke 3).People who intake high levels of polyunsaturated fatty acid are at less risk of a cerebral infarction than those who take high levels of saturated fatty acid.The polyunsaturated fatty acid / saturated fatty acid (P/S) ratio is an index of accurate fat intake 2, 3,20,28).The proportion of saturated, monounsaturated, and polyunsaturated fatty acids of every group in the NILS-LSA was not much different from the amount of fatty acids of the RDA 28) (30: 40: 30).It appears that the nutritional intake levels and patterns in the NILS-LSA were not extremely different from average Japanese people.
We assessed food and nutrient intake in the NILS-LSA through 3DR.The dietary intake of individuals varied from day to day when superimposed on an underlying consistent pattern [28][29][30][31].We also used a FFQ in the NILS-LSA because current and past intake or food habits could be measured by FFQ.We intend to report the result of the FFQ in the near future.

Figure 2 .
Figure 2. Proportion of fatty acid in the NILS-LSA.

Table 1 -
1. Daily intake of food of the respective food groups in the NILS-LSA (g/day).

Table 1 -
2. Daily intake of food of the respective food groups in the NILS-LSA (g/day).
by gender and age.The age trend was much clearer for nutrients than for daily food intake.For males in the 40 to 49 yr group, fat, and total fatty acid (TFA) were significantly higher than in other age groups, while total dietary fibers (TDF) were significantly lower.Energy, protein, fat, cholesterol and niacin in the 70 to 79 yr group were significantly lower.Energy, protein, fat, TFA, cholesterol, carbohydrate, vitamins E, B1, and niacin trended to decrease with age, whereas TDF, ash, calcium, vitamin A, and vitamin C increased.

Table 2 -
1. Daily energy and nutrient intake in the NILS-LSA.

Table 2 -
2. Daily energy and nutrient intake in the NILS-LSA.