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Sugar and Aging
Michael Lam, MD, MPH
www.DrLam.com
(READING TIPS: For fast reading, scan through the topic headings in BOLD BLACK, important conclusions in BOLD
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the respective LINKS in the Contents.
| Before You Begin
Information presented here is for general
educational purposes only. Each one of us is biochemically and metabolically
different. If you have a specific health concern and wish my personalized
nutritional recommendation, write to me by clicking
here. |
Contents
Introduction
Sugar in the Body and Diet
Sugar vs. Carbohydrates
Starch vs. Carbohydrate
Carbohydrate Breakdown and Storage
How Much Carbohydrate and
Food Energy Is Needed?
Classification of Carbohydrates
A. Simple versus Complex Carbohydrates
B. Paleocarbs vs. Neocarbs
C. High vs. Low Glycemic Index Foods
What is "Normal" Blood Sugar
Level?
Effects of High Blood Sugar
A. Increase in Diabetes
B. Increase in Cancer
C. Increase in Free
Radicals and Reduced Antioxidants
D. Increase AGEs
E. Increase in Heart Disease
What You Should Do
Introduction
Common table sugar represents about 20 to 25 percent of the daily caloric
intake of the average American. This translates into the equivalent of half
a pound a day and over 5 tons in a lifetime. In the early 1800's, the average
sugar consumption was 12 pounds per person annually. This increased to 124 pounds
in 1980 and to 152 pounds in 1997. It is
estimated that 75 percent of all sugar we consume comes from processed food.
Studies have linked a high sugar
intake with an increased risk of diabetes, cardiovascular disease, cancer, and
premature aging. Is this pure coincidence, or is the association real?
Sugar
in the Body and Diet
Sugar is a generic term used to
identify simple forms of carbohydrates, which includes fructose, glucose, galactose,
maltose and sucrose (white table sugar). The type of sugar and its rate
of breakdown can affect the body greatly. For example, table sugar (sucrose)
is considered nutritive as it contains calories, although it does not contain
vitamins, minerals or fiber. Another sugar type known as glucose has the
ability to break down quickly in the stomach and later be pumped across
the intestinal wall directly into the bloodstream. This process rapidly raises
blood-glucose levels, which causes the blood sugar level to spike. On the other
hand, fructose, which is sugar derived from fruits, gets into the body and is
slowly absorbed in the gut. It is then converted to glucose in the liver.
This makes fructose a "time-release food" as it delivers
calories at a gradual rate. A complete understanding of sugars and how they
affect our body is critical to the study of how sugar influences aging.
Sugar
vs. Carbohydrates
Carbohydrates are merely different
forms of sugars linked together in polymers.
Most people will consider sweets and pasta as carbohydrates. Most are not aware
that fruits and vegetables are also considered carbohydrates as well. In reality,
sugar, sweets, pasta, vegetables and fruits are all carbohydrates.
This confusion is compounded when
one considers that a carbohydrate diet consisting
mainly of green leafy vegetables is good for anti-aging. On the other hand,
a carbohydrate diet consisting primarily of white rice, potato, pasta, cakes,
ice cream, and bread is a negative fountain of youth.
While
both “good?and “bad?carbohydrates are classified in the same general group,
the effects on the body are totally different. To put matters into
proper prospective, any discussion on carbohydrates must clearly address
the specific kinds of carbohydrates in question.
Starch
vs. Carbohydrate
Starches are the most basic form
of carbohydrates. It is found in all fruits, vegetables, grains and legumes.
Starch is broken down in our digestive tract into small molecules of glucose,
which are then absorbed and transported into cells for energy production.
Many fruits and some vegetables contain
significant amounts of glucose and fructose, as well as a disaccharide called
sucrose (ordinary sugar), which contains both glucose and fructose.
Our bodies have been accustomed
to metabolizing about 300 grams of glucose (mostly from starchy foods) every
day for thousands of years.
We have always consumed some fructose,
often in the form of fruits and honey. Until about 200 years ago, the average
daily intake of fructose was only eight grams a day. As ordinary sugar (sucrose)
from sugar beets and sugar cane began to be readily available, the daily intake
of fructose raised 10 fold to 75 grams a day. The problem is further compounded
since the 1970s, when high fructose corn syrup was introduced as a substitute
sweetener. About 9% of the average dietary calorie intake now comes from
fructose.
When sucrose is ingested, it reacts
with water to generate glucose and fructose in equal amounts. Each 100 grams
of sucrose produces 53 grams of glucose and 53 grams of fructose. Sucrose is
called a disaccharide for this reason. The ingestion of 100 pounds of sugar
(sucrose) per year translates into 125 grams per day and 66 grams of fructose.
With about 8 grams added on from fruits and honey, the total average intake
per day now becomes 74 grams. Our body is
used to metabolizing only eight grams of fructose a day. The nearly 10-fold
overload has caused many health problems, which we will discuss below.
Carbohydrate
Breakdown and Storage
Carbohydrates
break down into glucose, which is the primary fuel the body needs to keep it
operationally functional.
Certain organs require more fuel than others to run. The brain utilizes almost
two thirds of the circulating carbohydrates in the bloodstream to keep it functioning.
Any excess carbohydrates not needed
are stored as glycogen (a storage form of glucose). Glycogen is stored in the
liver and the muscles. When the brain needs fuel, the glycogen in the liver
is broken down and transported to the brain for energy.
How much carbohydrate can you store?
The total storage capacity of the body for carbohydrates is limited. An
average person stores about 300 to 400 grams of carbohydrates in the muscles,
which cannot be utilized by the brain for energy. Only 60 to 90 grams are stored
in the liver for glucose conversion, equivalent to about two cups of cooked
pasta or three typical candy bars. This is all the body has in reserve to keep
the brain working properly.
Once the glycogen levels are filled
in both the liver and the muscles, excess carbohydrates are converted into fat
and stored in the adipose tissue. Hence, excess carbohydrates become fat.
In modern day society, it is sugar that makes
a person fat much more that the amount of fat a person consumes.
How
Much Carbohydrate and Food Energy Is Needed?
The key function of carbohydrates
is to provide energy for the body. Julius Robert Mayer, a German physician,
initially discovered the concept of food energy in 1842. The energy values of
a food can be determined by burning a set amount of food and measuring the amount
of heat produced. The common energy value is expressed in kilocalorie and is
based on the burning of 100 grams (or 3.5 ounces) of the food. It is determined
that approximately 900 kcal is generated per 100 gram of fat and 400 kcal per
100 gram of carbohydrate and protein intake.
There
are only four macronutrients we consume on a daily basis - water, fat, protein,
and carbohydrates. Out of these, only carbohydrates are nonessential to the
human diet. One can survive
for long periods of time without carbohydrates provided that protein and fat
needs are met, for these two are ultimately broken down to form building blocks
of carbohydrates as food energy for the body.
An intake of 300 grams of carbohydrates
yielding 1,200 kcal would provide 50 percent of an average daily requirement
of energy in an average American diet. A 2,500-calorie diet with 20 percent
of energy provided by protein (about four ounces or 120 grams) will generate
about 500 calories of energy. The amount of protein needed to sustain normal
bodily function can be readily supplied in four ounces of meat. The average
American consumes more protein than is needed.
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