Seaweeds are a part of traditional Japanese food. Animal studies have found that intake of
seaweeds or an extract of seaweeds lowers blood pressure
. Its relevance in
adults has however not been established due to inconsistent results from
various conducted studies.
Japan conducted a study to assess the benefits of a diet of seaweeds on blood
pressure in children between the ages of 3 and 6 years. This age group was
selected keeping in mind that early control of blood pressure through diet
could reduce the incidence of hypertension in adulthood.
Baseline blood pressure was recorded before the
study. Height and weight were either recorded or the details were obtained from
parents, and body mass index was calculated. Information regarding the child's
lifestyle and health status was obtained from the parents. Physical activity
was recorded based on an outdoor playtime checklist.
Food intake of the children was recorded by the
parents for 3 days covering 2 consecutive weekdays and 1 weekend day.
Blood pressure was measured once in the midmorning.
Depending on the quantity of sea weed consumed, the
children were divided into three groups - low, middle or high intake.
which was completed in 417 children, found that boys with middle and high
intake of seaweed had lower diastolic blood pressures as compared to those with
low seaweed intake. Systolic blood pressure and pulse was not associated with seaweed
intake in boys.
In the case of
girls, those with high seaweed intake had significantly lower systolic blood
pressures than those with low seaweed intake. The diastolic blood pressure of girls with
low seaweed intake was also higher than those of middle and high intake of
Intake of salt, other diet or lifestyle factors like
sleep and physical activity, did not affect the apparent effect of seaweed on
The study thus
indicates that seaweeds could influence blood pressure in children. However, it does have some
shortcomings. The dietary record was maintained for a very small duration.
Blood pressure was measured only once following the baseline measurement.
Studies carried out for longer durations could provide a clearer picture
regarding the benefit of seaweeds on blood pressure.
It appears to be very early to decide, based on this
study alone, whether seaweed intake in children could affect blood pressure in
later adulthood. Further studies are required to establish this beneficial
effect of seaweeds.
1. Wada K, Nakamura K, Tamai Y, Tsuji M, Sahashi Y, Watanabe K, Ohtsuchi
S, Yamamoto K, Ando K, Nagata C. Seaweed intake and blood pressure levels in healthy pre-school Japanese
children. Nutr J. 2011 Aug 10;10:83.