Evening star., 1939-12-05
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
BIZ Thomas r. Henri.

NuU StUOy
By Thomas r. Henry.
Experiments with a human volunteer
to determine the relative burning EN-
cheney" Of the sugar and starches In
various types of foods. in which hitherto
unexpected differences were detected by
delicate metabolism measurements. are
reported by the Carnegie Institution Of
Washington.
The results will form part of the an
nual exhibit OF scientific accomplish
mei1ts during the year, which viii follow
the annual meeting Of the trustees De-
cember Is.
Sugar and starches are the coal" Of
life They are seldom eaten in pure
form, however, and the body itself must
extract them from the chemical complex
Of the various foods eaten
Weights required to get the same
amount Of lifes fire from different COM
mon foods, the experiments show, differed
greatly The man had to eat only about
five ounces Of boiled sweet potato, for
example, to get an ounce OF burnable
sugars and starches, whereas he had to
eat 81 ounces of boiled carrots and "a
ounces of boiled beets The required
weights of raw white potato and raw
carrot were somewhat less than those
Of the same vegetables when cooked.
This may have been because soluble
sugars and starches leached from the
vegetables while they were. cooking, or
because the vegetables themselves took
up water while they were boiling. On
the other hand, the required weights Of
dried dates and figs were but little more
than those of cane sugar and dextrose.
Hitherto, 1t is pointed out in the
Carnegie report most knowledge of the
processes of combustion within the body
has come from studies made with pure
sugars, while little has actually been
known regarding the burning of the
more complex hydrocarbons.
The amount of carbohydrates burned
In the body before the man ate any food
that is, about 16 hours after his supper
averaged four-hundredths of an ounce
every Is minutes In the successive Is
minute periods after eating the increases
in carbohydrate combustion above this
baseline came most quickly and were
greatest with cane sugar and dates. After
eating such foods as white potato, rice
and macaroni, the increases per Is min
utes were not 50 great and did not occur
80 soon. but persisted for long time.
With nuts the increases were small but
continuous.
The initial increase in carbohydrate
combustion was greater after raw carrots
than after boiled carrots, but in both
instances 1t was at about the same level
in the last hour of the three-hour period
With boiled white potatoes, the increase
was at higher level than with raw
white potatoes throughout the entire
time
In the experiments with parsnips there
was delay in the digestion. The maxi
mum increase in carbohydrate combus-
ton did not occur until the third hour
after eating, although there was a
marked increase during the first hour.
The rise in the first hour, the Carnegie
experts believe, probably can be ascribed
to the easily soluble materials in the
parsnips. and the further rise in the
third hour to the subsequent absorption
Of digestible carbohydrates.
The total amounts Of carbohydrates
burned during the first three hours were
greatest in the case Of sweet vegetables
-beets. carrots and parsnips They we're
smallest with rice, macaroni, raw white
potatoes and nuts. For dates, cane
sugar and dextrose the total amounts
were only about two-thirds those OBJ
served for beets and carrots
With raw carrots the total amount
was slightly greater than with boiled
carrots, but with raw white potatoes the
amount was only about two thirds that
with boiled potatoes. 1t is generally be-
heved that the cooking Of vegetables in
creases their digestibility. The differ
ence between the two raw foods, the
Carnegie experimenters believe, is prob
ably ascribable to the difference In the
nature of the carbohydrate content car
rots having more soluble carbohydrates
than starch and white potatoes being
composed predominantly of starch.
With nuts the total carbohydrate COM
bustion was greatest with cashew nuts,
probably because this nut contains a
somewhat larger proportion of sugars
and a smaller proportion of fat than do
the others. In general when the food
carbohydrates are soluble sugars they
are most quickly available to the body,
but the increased carbohydrate COM
bustion lasts a short time. When the
food carbohydrates are chiefly starch,
they are more slowly available. but the
increased combustion lasts a longer
time. When the food consists predom-
inantly Of fat, as with nuts, the fat
seems to hinder the absorption and