THINKING LAB
Enzymes and Diet
Background
In 1963, Lithuanian-American Ann Wigmore spearheaded a
dietary movement in the United States called Living Foods.
She based her teachings about diet on her belief that cooked
foods cause most mental and physical illnesses, saying that
proteins and enzymes are destroyed during the cooking
process. The diet she recommended is a vegetarian one,
including sprouted grains and beans, vegetables, fruits,
nuts, wheatgrass juice, and dehydrated snacks.
Wigmore’s philosophy found an appreciative audience in
North America. Bookstores now carry many raw foods diet
cookbooks, restaurateurs have set up cafés serving raw
foods, and alternative health-care practitioners often
recommend raw food diets to help people lose weight and
prevent disease. The raw foods diet has been extended to
apply to pets — some veterinarians insist that dogs and cats
are unhealthy because they do not eat enough raw foods.
Vancouver veterinarian Julie-Anne Lee says, “Dogs and cats
eat raw food in the wild and hunting cats naturally eat raw
meat.” She argues that only a raw foods diet produces the
anti-bacterial enzymes in the gut and mouth that domestic
animals such as dogs and cats need to be healthy.
While some, such as Dr. Lee, extol the virtues of raw foods
for people and animals, others scoff at the idea, saying
that people have been eating cooked foods for centuries.
Skeptics point out that although people do need enzymes
to digest their food, cells make enzymes for that very
purpose. Some veterinarians also dismiss the need for raw
foods for pets, saying that pets have become accustomed
to a “domestic” diet, and would not function well on a
“wild” one.You Try It
1.Find out more about the Living Foods diet. Research
web archives and dietary journals, and try to interview
dietitians and health-care practitioners. Summarize the
main concepts behind the raw foods diet.
2.Using your knowledge of the properties and functions
of enzymes, review what you learned in your research.
Prepare a report answering the following questions: Is a
diet of raw food healthy for people? for dogs and cats?
Why or why not?
3.Investigate a particular food and the enzymes it
contains to ascertain whether it would be more
beneficial to eat this food raw rather than cooked.
Examples could be pineapples (containing the enzyme
bromelain), tomatoes, soybeans, or broccoli. Consider
also raw meats and fish.
4.Some enzymes break down as soon as they enter
the digestive system. For example, lactose-intolerant
people, who must ingest a lactase enzyme preparation
before consuming dairy products (which contain
lactose), should not do so too far in advance of eating
a dairy product. This is because our own digestive
enzymes begin to break down the lactase enzyme as
soon as it enters the digestive system. Apply this
knowledge, as well as a basic review of the digestive
process, to the information you found for question 3.
Do the enzymes in the raw food that you researched
break down before they have a chance to work in the
digestive process?Chapter 2 Enzymes and Energy • MHR 45the bonds between peptide chains in their enzymes
are relatively strong and able to withstand the
extreme temperatures. These enzymes are therefore
called thermostable enzymes.
Thermostable enzymes could operate above the
growth temperature for pathogens that otherwise
can contaminate foods. Potential applications of
this knowledge might include development of food
products that could be processed at higher
temperatures, and are more resistant to microbial
contamination (such as E. coli). Thermostable
enzymes may also be useful in drug synthesis.
Such enzymes may be able to catalyze reactions
more effectively, affording higher productivity.
They may also last longer and could possibly be
re-used. In the next Thinking Lab, you will conduct
research into the sources of enzymes in foods.Perhaps the Thinking Lab on enzymes and diet can help
you select a topic for the Biology Course Challenge. Look
ahead to page 544 to see how you can start preparing for
the Challenge.COURSE CHALLENGE