This presentation explores some of the factors that influence how long a human being lives, what affects the length of our lives, nutrition effects on life span and how to use diet and nutrition to stay healthy and live long.
Diet and Nutrition II
Nutrition and Life Span
Dr. Madhumita Sen
At the end of this lecture the student
What life span means.
What are the factors that govern life-
How nutrition affects life span.
What are the dietary changes needed
to keep a long and healthy life.
What is Life-span?
The life expectancy of a particular species is
Human life-expectancy is about 120 years.
Life span is an epidemiological standard.
It is measured as the average age of death in
a population cohort.
The goal of medicine is to prevent disease,
relieve suffering, and prolong life.
Life expectancy equals the average number of
years a person born in a given country would
live if mortality rates at each age were to remain
constant in the future.
Worldwide, the average life expectancy at birth
was 67.88 years (65.71 years for males and 70.14
years for females) over the period 2005–2010
according to United Nations World Population
Factors affecting Life-span
Human life-span is affected by:
1. Public health
3. Infant and childhood mortality
5. Risky behavior
7. Disease prevalence like infections, cancers,
diabetes, heart disease, etc.
In August 2007, the National Commission on Prevention
Priorities found that over 100,000 lives per year could be
saved through intensifying five services to 90% of the
Those services were:
1. smoking cessation counselling;
2. breast cancer screening in women over 40 years of age;
3. screening for colorectal cancer in adults ≥50 years of
4. influenza immunizations in adults ≥50 years of age;
5. the use of aspirin in high-risk cardiovascular patients
The top ten causes of death in the
Stroke (cerebrovascular diseases)
Chronic lower respiratory diseases
Accidents (unintentional injuries)
Alzheimer's disease and dementias
Chronic renal failure
"Bad men live that they may eat and drink,
whereas good men eat and drink that they may
In 1978, Strasser coined the term 'primordial
prevention', referring to prevention attained
through a self-directed lifestyle that did not allow
risk factors to develop in a population.
Many people experience some decline in health
with advancing age (usual aging), some maintain
very good health (successful aging), and others
experience morbidity or disability in old age that is
quite severe or quickly progressing (pathological
Life span and aging is composed of multiple
indicators (including chronic disease, physical
function, depressive symptoms, social support,
social participation, and economic satisfaction)
and that there are multiple trajectories for
successful aging over time among older adults.
List by the World Health Organization (2011)
Country Overall life
1 Japan 104 79 12 86 1
1 Switzerland 83 80 4 85 2
4 Singapore 82 80 4 85 2
4 Iceland 82 81 3 84 9
4 Australia 82 80 4 84 9
73 Thailand 74 71 82 77 75
73 Malaysia 74 72 67 76 87
Reversible Risk Factors in Aging
Tobacco use Hypertension
Cancer Excessive alcohol
COPD Insufficient physical
Diabetes Unhealthy diets Raised cholesterol
Sleep lack Stress/anxiety
Add life to years
The risk of heart disease, cancer, stroke, and
diabetes can be reduced substantially by eating
nutritious natural foods, maintaining a normal
weight, exercising regularly, and not smoking.
The chance of death can also be decreased by
avoiding drugs, alcohol abuse, pollution, violence,
At the same time, it is important to practice
good hygiene, get competent medical care, get
protective vaccinations, and avoid risky behavior
that can result in accidents or infection with the
viruses that cause AIDS or hepatitis.
Illnesses Linked to Poor Diet
Numerous studies have proven that eating the right
foods can decrease the likelihood of developing
certain diseases. Some of these are:
1. Heart disease, hypertension and stroke: This can
be caused by the intake of too much salt, high
cholesterol and fatty foods
2. Osteoporosis: This affects mainly older women, but
its effects can be mitigated by consuming calcium
3. Cancer: A number of poor food choices are
linked to various types of cancer such as bowel
4. Alzheimer’s disease and Dementias
Can we prolong life?
The only definite known intervention that can
prolong life is starvation!
Studies at the molecular level have shown that
several genes in the sirtuin class, create enzymes
that increase the activity of the mitochondria and
slow the cell's aging process.
These genes are activated during calorie restriction.
However, calorie restriction can create problems of
Dangers of Under nutrition
Stunting of growth and in children, poor mental
Malnutrition, anorexia, listlessness,
Death by starvation
Development of nutritional deficiencies
Reduced body’s ability to cope with stress
Dangers of over nutrition
Of course, obesity is an even bigger risk to life!
Obesity can cause chronic inflammatory
states which leads to:
1. Cancers of uterus, breast, colon, prostate,
liver, pancreas, gall bladder.
2. T2DM and metabolic syndrome.
3. Coronary artery disease, heart attacks.
4. Hypertension, strokes.
Dangers of obesity Contd.
6. Non-alcoholic Fatty Liver disease.
8. Reproductive problems. Poly Cystic Ovarian
syndrome (PCOS) in women, low sperm count in
9. Obstructive Sleep Apnoea and pulmonary
10. Gall bladder disease.
So how much should we eat?
The amount of food that can be consumed has
1) low enough to cause death from starvation, or
2) high enough to lead to obesity.
The amount of food associated with the
longest life span is somewhere between these
The chances of survival are increased just by
maintaining a lean body.
Should provide the right quantities of protein,
fat, carbohydrates, vitamins, minerals, fiber,
and probiotic bacteria to maintain a healthy
body and to sustain the desired level of activity
for the best quality of life.
Recommended Diet of 2000 calories per day,
consists of 25% protein, 15% fat, and 30%
carbohydrate, 30% as vegetables, fruits and
A new study suggests eating a Mediterranean
diet might increase lifespan.
The findings, published in the journal AGE, show
that elderly people who eat a Mediterranean
diet -- which is high in fish and vegetables and
low in animal products like milk and red meat --
have about a 20% increased chance of living
longer compared with their non-Mediterranean-
Fiber-rich, "plant-strong" diet could
National Cancer Institute researchers found that
those aged 50 to 71 who ate at least 26 grams of
fiber a day had a 22 % lower risk of dying over 9
years compared with those who ate 13 grams of
fiber a day or less.
Whole grains like oatmeal, wheat bran, and barley
have a real health impact. They're rich in
antioxidants like selenium and zinc that protect
tissues from oxidative damage which is common in
chronic diseases such as cardiovascular disease,
diabetes, rheumatoid arthritis, and Crohn disease.
Effects of dietary restriction on mammalian tissues:
Liver: Increase in gluconeogenesis and
glycogenolysis . Decrease in glycolysis
Muscle: Increase in mitochondrial biogenesis and
respiration. Increase in β-oxidation of fatty acids
Increase in protein turnover
Fat: Decrease in storage of triglycerides
Decrease in secreted leptin
Increase in secreted adiponectin
Pancreatic β-cells: Decrease in secreted insulin
Brain: Decrease in pituitary secretion of growth
hormone, thyroid hormone, gonadotropins
Increase in adrenal secretion of corticosteroids
Whole organism: Increase in insulin sensitivity and
decrease in blood glucose
Increase in metabolism
Lessons from Okinawa
Known as "the land of the immortals", Okinawa
boasts 900 people aged 100 or over, the highest
number of verified centenarians in the world.
Those who live there eat most of their food lightly
While they do eat small amounts of animal
products, they consume it mostly raw, such as fresh
They eat more tofu and soya products than any
other population in the world, and a vast amount
of different vegetables and fruits.
The Okinawans are physically active, and have a
stress-minimising spiritual outlook.
They live mostly in villages, allowing for a relaxed
and rural way of life, with a strong sense of
community, sharing the joys and hardships of their
They have a deep respect for age, with elders
playing an important role in the community.
When to eat
One of the leading theories of aging, the glycemic
theory, states that excess glucose leads to pathological
changes by binding with proteins and
creating advanced glycation end-products (AGEs).
This has motivated many nutritionists to advise
prevention of excessive rise of glucose after eating.
Some do this by eating small meals frequently, a
technique called "grazing", and by increasing their
intake of fiber to slow the absorption of carbohydrates
from the intestine.
Does Fasting help?
Recent research on eating only every other day,
called "Intermittent Fasting", has shown beneficial
effects that met or exceeded those of calorie
restriction including reduced serum glucose and
One important aspect of intermittent fasting is
that it does not require much calorie restriction on
the non-fasting days and does not cause stunted
What about Supplements?
The free-radical theory of aging suggests
that antioxidant supplements, such
as Vitamin C, Vitamin E, Co-Q10, lipoic acid,
might extend human life.
Some people think that if you take vitamin pills
by the handful, you don’t have to bother
watching what you eat.
However, combined evidence from several
clinical trials suggest that β-Carotene
supplements and high doses of Vitamin E and B-
complex increase mortality rates.
As supplements are either made from natural
substances or mimic substances produced by our
bodies, many people assume they cannot do any
Many studies have since shown that vitamins from
supplements do not act on the body in the same
way as vitamins from foods.
Calcium supplements - often prescribed for
osteoporosis - could raise the risk of heart attacks by
30 per cent.
This increase is due to the risk of calcium
supplements accelerating the hardening of blood
Studies showed that older women who took a daily
vitamin supplement, even just a multivitamin, had an
increased risk of dying of cardiovascular disease
The link between supplement intake and death risk
was strongest with iron.
Taking vitamin E supplements significantly increased
the risk of prostate cancer in healthy men even after
they stopped taking them.
A 2004 Cochrane review of studies found there was
not enough evidence that 2000mg vitamin C
supplements prevented colds in the general
More recently, the US Women's Health Study found a
link between vitamin C supplements and an
increased risk of hardening arteries in some people
What about Hormones and Phytochemicals?
Other substances proposed to extend lifespan
include oxytocin, insulin, human chorionic
gonadotropin (hCG), and erythropoietin (EPO).
However, hormone supplements have shown no
benefits in any study.
Phytochemicals have many natural
Resveratrol is a sirtuin stimulant that appears to
Is there an Ideal Weight for Longevity?
The least mortality was found with a Body Mass
Index 23.5 to 24.9 in men and 22.0 to 23.4 in
The rate of suicide has been found to be
greater for men with BMIs below 21.
Being underweight or overweight is associated
with increased mortality.
The role of Exercise
The amount of food consumed and the level
of exercise are the two components of the
diet equation that can be controlled
In general, people who exercise regularly
have a lower death rate than sedentary
people, regardless of their weight.
A recent systematic review, first-authored by TJ
Saunders of Obesity Panacea, found that a
single day of bed rest is sufficient to raise
triglycerides, and that 2 hours of sitting increases
insulin resistance and impairs glucose tolerance –
moving the body closer to a diabetic
When sitting, dietary fats are taken up only by
adipose tissue. When standing, they are taken up
by muscle and adipose tissue both.
Time spent standing helps to push fat into muscle
cells as much as vigorous daily exercise!
Research shows that remaining active can help to
maintain both mental and physical health.
Keeping up the activities you enjoy doing will help
to maintain physical fitness and preserve muscle
Preserving strength will help to maintain your
Remember, activity doesn't necessarily mean
joining an exercise class.
Gardening, walking to the shops and housework
can all count as types of activity too.
Don’t worry,Be Happy!
Another very important contributor to a long
and healthy life, apart fro diet and exercise, is
being stress free.
Therefore, stress reduction methods such as
meditation, prayer and social interactions are
an integral part of longevity strategies.
Sleep Is Good
Sleep is highly beneficial for a healthy lifespan.
Consequences of poor quality or insufficient sleep
Higher rates of cancer.
Impaired immunity and vulnerability to infection.
Higher rates of heart disease.
Higher all-cause mortality.
Faster cognitive decline with age.
Shortening of telomeres.
Higher rates of diabetes.
The best six doctors anywhere
And no one can deny it
Are sunshine, water, rest, and air
Exercise and diet.
These six will gladly you attend
If only you are willing
Your mind they'll ease
Your will they'll mend
And charge you not a shilling.
Making our life span approximate our
life expectancy is a goal we all aim for.
Methods used essentially co-relate with
leading a healthy life.
They consist of a balanced diet,
exercise and healthy lifestyle measures.