L ECTURE 1 (Jan. 7 ),
Introduction by Joe Schwarcz
What should we put on our plate?
• Many look up to the USDA (United States Department of
Agriculture) for dietary advice.
o Food pyramids have been replaced by the “food plate”,
which gives us an idea of the proportions of food
components we should consume in a healthy diet.
o It has been widely criticized though for not being detailed enough, for suggesting
that dairy should be consumed at every meal, and for not considering fats at all.
• Alternative healthy eating plate of the
Harvard School of Public Health:
o They include healthy fats.
o Don’t advocate consuming dairy
o More detailed info about types of
grains one should be eating, etc.
o No political/industrial affiliations.
This is not the case with the
USDA→ afraid to be
against sugar or white flour.
• UK has its own “eatwell plate”.
• High-fat low-carb diet plate (acc. toAtkins’
people). It has some merit in weight loss.
• Vegan plate (no animal products).
• Paleo dieters suggest that we should eat the way
our cavemen did. Diet based on meat consumption.
• Low calory diet: Key to longevity.
• Canadian Food Guide suggests eating, for
instance, lots of carbohydrates (despite many
scientific opinions against this idea).
• Despite a lot of research, there is still much controversy. E.g. of some agreed facts: the
less sugar, the better. Trans-fats are not beneficial.
• Nowadays, there is simply too much information. We
can back up with evidence almost anything we want. There is no shortage of food in NorthAmerica.
• We have a wide variety of fruits, vegetables (cooked or raw), meats (chicken, beef,
spiced, temperature of cooking, processed meat, etc.), breads (refined flour, whole-grain
flour), cheeses, deserts to pick from!
• Conundrum of food additives: preservatives, artificial flavours and colours.
• People around the world have different diets. Scientists try to relate diets to the health of
Alot of advice about nutrition is available in books.
• Wheat Belly: avoiding anything • Sweet Poison, Why Sugar Makes Us
made with wheat/grain. Fat: too much fructose in liver
• Milk, The Deadly Poison • Sweet Deception: artificial
• Toxic Oil sweeteners are supposed to be
• The whole soy story: soy is said to carcinogenic.
contain many dangerous toxins. • Beware of the food you eat.
• My Beef with Meat
What is THE healthy diet?
• We don’t lack information; it’s what we do with it.
• When we have little or too much information, it leads to confusion. We
need the RIGHT amount of information.
• We used to be concerned only about the taste of food. Now, we’re very
critical about everything we eat. We wonder if we should eat vitamin C to neutralize
nitrites (if contained in our food) so that they get converted into nitric oxides, for
• Eating has become a clinical experience; we want to know the cholesterol content of
food, the vitamin content, whether our food is genetically modified or not, etc.
You are what you eat: Statement of scientific fact. Food is the only raw material that goes into
our body, so we are constructed of what we eat. Obviously, there has to be a link between food
and health, although food is not the only determinant of health. Genetics play a huge part, but
food consumption is what we can CONTROL.
• We are a large “bag” of hundreds of thousands chemicals.
o In an apple bite, there are about 300 different compounds.
o When we sniff coffee, we smell over a thousand different compounds.
You are what you read: our knowledge comes from reading, so we
need to be selective about the information we read. We may learn one
day that it’s poutine that’s killing us, but the next day the news can
give us comforting information that we can avoid all disease if we eat
pomegranates, a miracle fruit! Only because it’s been used for a long
time, it doesn’t mean it’s been effective.
• One rule of nutrition: If it tastes good, you should be careful
and not eat too much of it. • Bible story (where it all started): The story is that of Eve temptingAdam to eat an apple.
The bible, however, never mentions the fruit of the tree of knowledge. It couldn’t have
been an apple however, since this fruit didn’t grow in that part of the world at the time;
apples were only introduced in the middle ages. It could have been pomegranates.
o Pomegranates contain natural aromatase inhibitors.
These types of inhibitors, when synthesized in the lab, can be used in medicine to
help treat breast cancer for example.
The multiplication of cultured breast cancer cells is reduced when bathed
in pomegranate juice. This observation is not sufficient enough for us to
extrapolate that pomegranates are
a preventative measure or
treatment for breast cancer.
This is the kind of claim
advertisers would use to sell the
fruit, but in doing so they lead to
• There is no miracle food, but it’s possible to
make any food sound that way by selectively
looking at the scientific literature.
o One could convince us that dried
apricots are the way to go.
o At the foot of the Himalayas, in Shangri-
La, the diet is very high in dried apricots
due to its availability. The book “Lost
Horizon” by James Hilton explores the
idea that people should live forever there.
People from that region claim to have impressive longevity (120-
30 years), but this cannot be verified since they do not have birth
Assuming it is true, we can then make the claim that dried
apricots contain a lot of beta-carotene, which is an
antioxidant and is beneficial for health.
Apricot pits have laetrile, which was once promoted as a
cancer remedy. The scientific research done by the
National Cancer Institute suggests otherwise (see next
• To prevent such confusion and misinformation, in science, we rely on peer-reviewed
literature. Not 100% true, since there is no guarantee that the submitted work has
actually been done and that the results are accurate; we have to assume that it has been
o Andrew Wakefield academic paper that scared people away from vaccination
wasn’t accurate in terms of what was actually done in the experiment. 2500 years ago, people were already concerned about what we should and shouldn’t eat.
• Hippocrates said, “Let Thy Food Be Thy Medicine.”
• People were even more concerned about food in those times, since they didn’t have
drugs, so the only way of improving their health was through selection of the right food.
• Less wisely, Hippocrates also argued that “lettuce cools the body and curbs the passion,”
that “pigeon droppings are great for baldness” and that “flax is great for the intestines.”
o Flax acts very effectively as a laxative, facilitating bowel movements and
o Flax seeds also contain beneficial omega-3 fats. These fats contain compounds
called lignans, which have anti-cancer effects (at least on cells in laboratory
conditions), and fiber, which are good for the intestinal health.
• Nutritional science: a mix of sense and nonsense. We simply have more of both now.
• We are continuously extrapolating from laboratory data, combining it with human
epidemiological evidence, which is quite often inaccurate being based on “recall”
(questionnaires/surveys) since we can’t remember frequencies of food consumption and
estimate amounts precisely.
o Alternative: use “food diaries” and write down what and when we ate.
• Details are important when analyzing scientific results.An example comes from a study
by Lillian Thompson from University of Toronto: risk of breast cancer is reduced by
dietary phytoestrogen (lignans and isoflavones) intake but
ONLY in premenopausal overweigth women.
• No geese lay golden eggs, but some chickens do: Omega 3 eggs.
o Egg yolk is burdened with cholesterol, which is often
linked (supposedly) to heart problems. Egg sales were
declining as a result of this association, so a new marketing angle was chosen.
o While egg sales were dropping, food with Omega 3 fats (mostly found in fish oil)
were very popular, because these fats were associated with reduced risk of irregular heart beat, reduced attention deficit disorder, and increased IQ in
children whose mothers have eaten omega 3 fats during pregnancy.
o Solution: incorporating flax seeds in the chicken diet, which contain a similar type
of omega 3 fats as that in fish oil. People’s attention was distracted away from the
cholesterol content of egg yolks.
The increase in the omega 3 content in eggs is not considerable, however.
To eat enough eggs so that their input in our omega 3 diet requirement is
significant would involve us consuming more eggs than we should (>5-7
eggs/week). So, it doesn’t matter what types of eggs we buy.
o We technically don’t need the chicken (i.e. the middlemen). We can
eat flax seeds directly, by sprinkling them over cereal, baking them
into bread or buying bagels with 20g of flax seeds – the amount
Dr. Thomson of UofT has shown to be beneficial to reduce breast
These bagels are better for us than sugary donuts which
contain a lot of trans fats, that are harmful for us, make us
gain weigth, and increase our blood cholesterol.
Adose-controlled study claimed that beta-glucan in oatmeal and
oat bran (outer covering of oat grain) could lower cholesterol.
Beginning of oat-bran mania; it became a quasi medicine (before,
farmers used to get rid of it by giving it to animals to eat).
• But HOW MUCH oat bran is there in the commercialized products? How much of them
should we eat to avail ourselves of the benefits?
o The active ingredient in the oat bran is a chemical called beta-
glucan, a form of soluble fiber.
o To ingest 3 grams of beta glucan – the quantity required for
lowering blood cholesterol – we would need.
1 cup of oat bran hot cereal.
3-5 muffins of oat bran muffins.
1.5 cups of oatmeal.
5 servings of cheerios (at which point this equals an overdose of sugar).
• The literature aimed at the consumers rarely talks about numbers and
only mentions what is good and bad for us.
o “Fit for Life” by Harvey and Marilyn Diamond: The writers
were, at the time, a married couple who portrayed themselves as
people protecting us from an unholy alliance between scientists
who try to undermine the health of the public. They
divorced later and each married a partner half their age.
E.g. of absurdity they wrote:
• “Within atoms & molecules reside vital
elements we know as enzymes. Enzymes
are not things, substances. They are the life principle
in the atoms & molecules of every living cell.”
(i.e.enzymes are the living entity in a food; cooking
a food or adding preservatives destroys enzymes). • “The greatest threat to your health is processed food. The day
science entered the food indudstry was a sad, sad day indeed.”
o No, it was a good day. Today, we have a better food supply
than ever in human history, if chosen wisely.
Sliced white bread is made with preservatives, e.g. calcium propionate (in bread), which to the
Diamonds were synonymous with toxins and poison.
• Although it’s obvious that whole-grain bread is better for us, preservatives are important
to prevent molds from forming and releasing very toxic metabolites.
• Before a chemical is added to a food as an additive, the baker has to submit a lot of data
to Health Canada and UFFDA(?) to be approved. Calcium propionate is an approved
food additive, since it’s actually produced by the body – they are metabolic breakdown
products of fats and are found in our sweat.
French lifestyle: Baguettes grow hard starting after 17 sec, since they have no preservatives.
• The French Paradox and beyond: Live Longer with Wine &
the Mediterranean Lifestyle by Lewis Perdue → describes how
Frenchmen who smoked more, exercised less, ate more butter-
filled croissants and stuffed geese livers have fewer heart
attacks than us? How is it that the coronary artery disease
(CAD) death rate is about ¼ of that in NorthAmerica? It’s
definitely not because French people watch Jerry Lewis more
than anyone else (!). We could plot a graph: the more Jerry
Lewis, the less heart disease, but this association doesn’t translate into cause-and-effect.
• The attribute in the French Paradox is to red wine. French people drink 30x more red
wine than we do in North America, which is said to protect them. We have the same
problem here: this statement is only an association and not a cause-and-effect
• Red wine contains resveratrol, an antioxidant with some anti-cancer
effect & cholesterol lowering, that “underlies” the lower CAD death rate.
o To confirm this is true, we would need to conduct a controlled
study: a group consuming resveratrol and a control group not
consuming it. We don’t have such evidence – look back to the
difficulties of epidemiological studies mentioned earlier.
o Marketers don’t wait for such explorations: resveratrol pills are already available
in health food stores. Not sure if these pills contain much resveratrol, since it’s a
very unstable compound.
• Ethanol (alcohol) in red wine is a known carcinogen (cancer-causing agent). Had alcohol
not been a natural product, but synthetic, and if producers tried to introduce it to the
market now, they would never have succeeded.
Remember: there are NO superfoods; it’s an invention of marketers and book writers.
• E.g. “The Cure is in The Cupboard: How to use Oregano for Better Health” by Dr. Cass
Igram → oregano is a medicine chest in a bottle. It can reverse many ailments, including: • It’s a MISLEADING CONCEPT however (there is no evidence for all that). The secret of
eating healthier is simply not as seductive as the idea of miracle foods existing.
Obesity is a real problem, especially in NorthAmerica. This condition is linked to cancer, heart
disease, and diabetes.
• Alot of it comes from the overconsumption of sugar (while until
now, fats were mostly blamed). The amount of sugar in soft
drinks, for example, is staggerring. Keep in mind that, although
the same amount of sugar is found in apple/orange juice, at least
there are some vitamins and minerals along with it.
• Another factor is how we cook food. High temperature is the
enemy of health. When we charcoal boil a steak, we introduce a
variety of heterocyclic aromatic amines and polycyclic
hydrocarbons, which lead to all kinds of health issues.
• Processed food:Astudy tells us that consuming an average of 60 grams of processed
meat (with nitrites) a day increases the risk of developing colorectal cancer by 50%.
o The vegetarian diet might seem the way to go, but many argue that this leads to
lack of the specific nutrients found in meat. Obviously, the more vegetables we
eat the better. We need to be more careful with fruits du