Contributing to Absolute Intake and Variance in Intake of Fat , Fatty Acids and Cholesterol in Middle-aged Japanese

On the basis of 351 one-day weighed diet records, we selected foods/recipes contributing to nutrients of interest for a data-based food frequency questionnaire by contribution analysis and multiple regression analysis. Total fat was largely of animal and vegetable origin, irrespective of analytic methods. Saturated fatty acid was mostly from animal and vegetable sources according to contribution analysis, and that of animal origin was the main contributor by multiple regression analysis. Mono-unsaturated fatty acid was substantially supplied by animal and vegetable products by either analytic method. Poly-unsaturated fatty acid, n-6 poly-unsaturated fatty acid and linoleic acid were found to be of vegetable origin and chicken egg according to contribution analysis; while vegetable oil and mayonnaise were the major contributors to variance in intake. Arachidonic acid was, however, mostly provided by animal sources including chieken egg and fish, irrespective of analytic methods. N-3 poly-unsaturated fatty acids and a -linolenic acid were of vegetable and marine origin. Eicosapentaenoic and docosahexaenoic acids were particularly from marine products, irrespective of analytic methods, except for chicken egg in docosahexaenoic acid by contribution analysis. Cholesterol was of animal and marine origin by either analytic method. Thus, foods contributing to absolute intake and variance in intake of fat, fatty acids and cholesterol differed considerably. J Epidemiol, 1999; 9 : 78-90


Foods
Contributing to Absolute Intake and Variance in Intake of Fat, Fatty Acids and Cholesterol in Middle-aged Japanese Yuko Tokudome 1, Nahomi Imaeda 2, Masato Ikeda 3, Ikumi Kitagawa 4, Nakako Fujiwara 5, and Shinkan Tokudome 5 On the basis of 351 one-day weighed diet records, we selected foods/recipes contributing to nutrients of interest for a data-based food frequency questionnaire by contribution analysis and multiple regression analysis.Total fat was largely of animal and vegetable origin, irrespective of analytic methods.Saturated fatty acid was mostly from animal and vegetable sources according to contribution analysis, and that of animal origin was the main contributor by multiple regression analysis.Mono-unsaturated fatty acid was substantially supplied by animal and vegetable products by either analytic method.Poly-unsaturated fatty acid, n-6 poly-unsaturated fatty acid and linoleic acid were found to be of vegetable origin and chicken egg according to contribution analysis; while vegetable oil and mayonnaise were the major contributors to variance in intake.Arachidonic acid was, however, mostly provided by animal sources including chieken egg and fish, irrespective of analytic methods.N-3 poly-unsaturated fatty acids and a -linolenic acid were of vegetable and marine origin.Eicosapentaenoic and docosahexaenoic acids were particularly from marine products, irrespective of analytic methods, except for chicken egg in docosahexaenoic acid by contribution analysis.Cholesterol was of animal and marine origin by either analytic method.Thus, foods contributing to absolute intake and variance in intake of fat, fatty acids and cholesterol differed considerably.J Epidemiol, 1999; In Japan, not only the incidence but its rates of chronic heart disease, cerebral embolism and cancers, including those of the colon, breast, prostate, endometrium and ovary, have recently increased 6,7).Such diseases have been alleged to be related to a westernized lifestyle, especially a dietary habit of overconsumption and/or imbalanced intake of fat, fatty acids and cholesterol 4.5).Thus, it seems useful to report foods contributing to absolute intake and variance/inter-individual variation in intake of fat, fatty acids and cholesterol in the middle-aged Japanese.

SUBJECTS AND METHODS
The subjects and methods employed in designing an SQFFQ were described elsewhere 1) and outlined here.A total of 351 (171 males and 180 females) middle-aged Japanese living in the Tokai area of Central Japan participated in a one-day WDR survey in autumn, 1994.
In all, 586 foods were consumed by the subjects.The intake of nutrients through food was computed by multiplying the food intake (in grams) or serving size and the nutrient content (per gram of food) as listed in the Standard Tables of Food Composition, Version 4 and the Follow-up of the Standard Tables of Food Composition, Version 4 8,9).First, CA for 31 nutrients was applied 10) and 252 foods up to 90 cumulative % contribution were selected.Those foods having apparently the same/similar nutrient contents were combined into 206 foods/recipes by research nutritionists, irrespective of the different cooking processes or appearances.Next, CA and forward MRA were applied 11-14) 183 foods/recipes with up to 90 cumulative % contribution as well as 0.90 cumulative multiple regression coefficient/cumulative R2 were chosen.Finally, 102 foods/recipes were included in the questionnaire.

RESULTS
Table 1 shows the intake of fat, fatty acids and cholesterol in addition to macro-nutrients by the 351 subjects.More nutrients were consumed by males than females.About 60 grams of fat was consumed, and the fat-energy ratio was calculated to be more than 25%.The ratio of fat sources according to animal: vegetable: marine was 4 : 5 : 1, and SFA : MUFA : PUFA was circa 1 : 1.5 : 1.The ratio of n-6 PUFA vs. n-3 PUFA was approximately 4 : 1.
Tables 2 and 3 show the top 20 foods according to cumulative % contribution and cumulative R2 for total fat, SFA, MUFA, PUFA, n-6 PUFA, n-3 PUFA, linoleic acid, arachidonic acid, a -linolenic acid, EPA, DHA and cholesterol, respectively.Figure 1 shows the curves of cumulative % con-tribution and cumulative R2 of the top 50 foods for corresponding fat, fatty acids and cholesterol.
In total fat, CA showed that chicken egg ranked at the top, followed by salad oil (mixed), vegetable oil (mixed), milk (whole) and mayonnaise (egg yolk type) (Table 2).On the other hand, fat of animal origin, including pork (ground meat), mayonnaise (egg yolk type), pork (Boston butt), and chicken egg, and salad oil (mixed), were major contributors according to MRA (Table 3).
SFA was largely supplied by animal sources, including chicken egg, milk (whole), pork (Boston butt), beef (chuck loin) and butter, and vegetable products, such as well-milled rice and vegetable oil (mixed) according to CA. Foods of animal origin, including milk (whole), pork (ground meat), beef (sirloin), butter, pork (Boston butt) and beef (chuck loin), were substantial contributors to variance in intake.
MUFA was equally derived from animal sources, such as chicken egg, mayonnaise (egg yolk type) and milk (whole) and vegetable products, including salad oil (mixed) and vegetable oil (mixed), irrespective of the analytic methods.
PUFA was largely provided by vegetable origins, such as salad oil (mixed), vegetable oil (mixed) and Tofu, and chicken egg according to CA; whereas safflower oil, mayonnaise (egg yolk type), vegetable oil (mixed) and mayonnaise (whole egg type) were the main contributors to variance in intake.
N-6 PUFA, a major fraction of PUFA, also originated from vegetable sources, including salad oil (mixed), vegetable oil (mixed), Tofu and well-milled rice, and chicken egg by CA.Safflower oil, vegetable oil (mixed), mayonnaise (egg yolk type and whole egg type) and salad oil (mixed) were major contributors by MRA.
N-3 PUFA was also provided by vegetable products, such as salad oil (mixed), vegetable oil (mixed) and Tofu, animal origin, including chicken egg and mayonnaise (egg yolk type), and marine sources, such as salmon by CA.Marine origin , including Pacific Saury, Japanese pilchard and young yellowtail, mayonnaise (egg yolk type) and vegetable oil (mixed) were substantial contributors to variance in intake.
Linoleic acid originated from the same foods as PUFA and n-6 PUFA, according to either analytic method .Approximately 50% of arachidonic acid was provided by chicken egg, followed by other animal origins, such as pork , chicken and milk (whole) by CA and MRA .
Alfa-linolenic acid was largely supplied by vegetable sources, including salad oil (mixed), vegetable oil (mixed) , mayonnaise (egg yolk type) and soybean products by CA and MRA.EPA was typically derived from marine products , such as fish, shellfish and seaweeds .DHA was also of marine origin, except for chicken egg, by CA; mostly marine sources by MRA.
Cholesterol was supplied by animal products , including chicken egg, mayonnaise (egg yolk type) and milk (whole) , and marine origin, such as squid , salmon and shrimp, irrespec-Table 1. Intake of macro-nutrients, fat, fatty acids and cholesterol by the 351 subjects.five of the analytic methods.

DISCUSSION
About 60 grams of fat was consumed by the subjects, and the fat-energy ratio was computed to be more than 25%, which is almost equivalent to the national average in the respective age groups 15), and slightly larger than the Recommended Dietary Intake (RDA) 16).The ratio of fat sources according to animal: vegetable: marine was 4 : 5 : 1, and SFA : MUFA : PUFA was approximately 1 : 1.5 : 1.The ratio of n-6 PUFA vs. n-3 PUFA was circa 4 : 1.These values nearly complied with the national average and the RDA; however, cholesterol consumed exceeded the RDA.
The total fat of 62.0 g in males and 57.7 g in females were greater than the sums of SFA, MUFA and PUFA of 52.5 g in males and 48.5 g in females, which was not fully attributable to the composition of triacylglycerols.It may be explained that the fatty acid contents for certain foods were not listed in the Standard Tables of Food Composition, Version 4 and the Follow-up of the Standard Tables of Food Composition, Version 4 8,9).Fatty acid of approximately 5 grams or 9 % in total fat was incalculable 17).We are now collecting information from researchers involved, including affiliated analytical chemists, and data currently published to fill up incomplete data.
In general, the curves of cumulative R2 and cumulative % contribution of fat intake saturated gradually.Fat is contained in various foods, whether of animal, vegetable or marine origin.But the former curves saturated rather faster than the latter ones, and much faster in EPA, DHA and cholesterol.This implied that food selection based on MRA seems more predictive and efficient than that based on , although absolute nutrient intake may be unavailable.
N-6 PUFA was approximately four-fifths of PUFA, and its major contributor was linoleic acid.N-6 PUFA and linoleic acid were substantially of vegetable origin.Arachidonic acid is also one of n-6 PUPA and essential fatty acids, like linoleic and a -linolenic acids, but synthesized from linoleic acid.Its dietary sources, however, were mostly derived from animal products, including chicken egg, milk, pork and beef.
N-3 PUFA and a -linolenic acid were largely provided by vegetable sources, except for chicken egg.EPA and DHA were mostly marine in origin, except for chicken egg in DHA.A Mediterranean diet is rich in a -linolenic acid 18,20); while the Japanese diet is rich in EPA and DHA 18,21) which endowed a decreased n-6 PUPA vs. n-3 PUPA ratio.This fatty acid balance as well as reduced intake of fat may explain a decreased  Our questionnaire inquires foodstuffs, partly recipes, frequency and portion size; therefore appeared unsuitable to administer it to individuals in public.Using the questionnaire, however, with aid of food models and pictures, a research dietitian is interviewing patients polypectomized in a randomized controlled trial to prevent the onset of adenoma/carcinoma of the colon.On the other hand, it will be self-administered to dietitians to clarify the association between diet and health/disease.For studies in individuals in public an abbreviated recipes-based SQFFQ focused on intake of fat and fatty acids are now being processed.

Figure 1 .
Figure 1.Curves of cumulative % contribution and cumulative R2 of the top 50 foods for selected fat , fatty acids and cholesterol.

Table 2 .
Cumulative % contribution of the top 20 foods for selected fat, fatty acids and cholesterol.

Table 3 .
Cumulative R2 of the too 20 foods for selected fat, fatty acids and cholesterol.
continued et al.