N-3 fatty acids are consists of α linoleic acid derived from cooking oil, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA) derived from fish oil. Animals can not synthesize these fatty acids in their body, then the lack of n-3 fatty acids leads to dermatitis. N-3 fatty acids not only compete with n-6 fatty acids but also have its own physiological effect. Therefore, the reference intakes has been set.
The approximate amount for 0-5 months infant has been set to 0.9 g/d by multiplying the standard mammalian amount 0.78 L/d to n-3 fatty acids concentration of breast milk 1.16 g/L. The approximate amount for 6-11 months infant has been set to 0.8 g/d by calculating the average of the approximate amount of 0-5 months infant and of 1-2 years old child based on the National Health and Nutrition Survey in 2010 and 2011.
Child and Adult
The approximate amount has been set to the median of n-3 fatty acids intake based on the National Health and Nutrition Survey in 2010 and 2011.
Pregnant and Lactation
The approximate amount has been set to 1.8 g/d, the median of n-3 fatty acids intake based on the National Health and Nutrition Survey in pregnant and lactation from 20108 to 2011.
α linoleic acid
There is a report of negative correlation between α linoleic acid and cardiovascular disease, 1 g/d increase of α linoleic acid intake results 10 % decrease of cardiovascular death. However, there are not enough reports for Japanese subject, then the target amount has not been set. Although the risk of prostate cancer, negative association of egg function and negative possibility of fertility have been reported, they are not determined. The effect of long-term intake of α linoleic acid is not clear.
EPA and DHA
The results of meta analysis on the relationship between EPA and DHA and cardiovascular disease is not consisted. The reports for Japanese subject are JPHC, JACC study and JELIS. The intervention study for stroke in Japanese is JELIS, that has shown not primary prevention effect but secondary prevention. There are meta-analysis of breast cancer cohort studies and report of risk reduction in the meta-analysis of colorectal cancer cohort study. In Japanese, decrease of liver cancer incidence and risk reduced of proximal colon cancer has been reported in JPHC. The association between n-3 fatty acid and depression and dementia is not clear.
Fish include such heavy metals as mercury, cadmium, lead and tin and such toxins as PCB and dioxins. There are another criterion for these harmful substances. Therefore, the Dietary Reference Intakes does not take account into these harmful substances.
Although target amount of α-linoleic acid had been set in 2010 edition, it has not been set in 2015 edition. Although they recommended the intake of grater than 1 g/d of EPA and DHA in 2010 edition, they have not been set in 2015 edition.
2015 edition and 2010 edition of the dietary reference of n-3 fatty acids are following table.
|Age||Approximate Amount||Approximate Amount|
|Age||Approximate Amount (g/d)||Target Amount (% energy)||Approximate Amount (g/d)||Target Amount (% energy)|
|18-29||≤ 2.1||≤ 1.8|
|30-49||≤ 2.2||≤ 1.8|
|50-69||≤ 2.4||≤ 2.1|
|70-||≤ 2.2||≤ 1.8|