Day 014 - 20 Jul 94 - Page 39


     
     1        revised.
 
     2   Q.   It goes on (and this we must remember is 3 years old)
               "High body mass index (BMI) (obesity), alcohol and
     3        smoking are important contributory factors to the
              development of hypertension."  That means high blood
     4        pressure, does it not?
              A.  Yes.
     5
         Q.   "In adolescents obesity may increase the sensitivity of
     6        blood pressure to dietary Na intake.  The lower Na intakes
              of 'less developed communities' with lower blood pressure
     7        than those seen in developed societies with increased
              incidences of hypertension may reflect different
     8        lifestyles rather than a causal relationship between Na
              intake and increased blood pressure, although more recent
     9        evidence is in favour of the latter."
              A.  Yes.
    10
         Q.   "After BMI and alcohol consumption have been allowed for,
    11        a relationship does exist between urinary Na excretion
              (assumed to be a marker of intake) and increasing blood
    12        pressure with age. However this correlation was not as
              strong as that found either between urinary potassium (K)
    13        excretion or urinary Na: K ----" What is Na K?
              A.  It is the ratio of sodium to potassium.
    14
         Q.   I should have read the word 'ratio'?
    15        A.  Yes.
 
    16   Q.  "Although restricted Na intakes reduce blood pressure in
              individuals with established hypertension, they do not do
    17        so reliably in those with normal blood pressure.  It has
              been calculated that a reduction of daily Na intake from
    18        3.9 to 1.6g might reduce sysolic blood pressure by 2.2 mm
              Hg ----
    19        A.  Mercury.
 
    20   Q.  " --- and diastolic pressure by 0.1 mm Hg, but recent
              evidence suggests this may be a considerable
    21        underestimate.  The Panel accepted the possibility that
              public health benefits such as reduced cardiovascular
    22        disease mortality might arise from such a change, but
              other interventions such as reduction of obesity,
    23        increased potassium, reduced energy takes, altered
              quantity and quality of fat intake and reduced alcohol
    24        consumption may also have at least as great an impact on
              such diseases.  The Panel cautioned against any trend
    25        towards incrased Na intakes.  The Panel further agreed
              that current Na intakes were needlessly high, and decided 
    26        to set DRVs on the basis of the balance of risks and 
              benefits which might practically be expected to occur, 
    27        given the prevailing socio- cultural environment."   What
              I would like to ask you about this is (I will come to what
    28        they say at 25.3.4 and 3.5 in a moment): As an approach to
              the question "What risks may or may not exist in the
    29        consumption of given quantities of a particular substance,
              the approach exhibited in this passage, does it or does it
    30        not commend itself to you?
              A.  Yes, it does, in the sense that you have to look at

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