You are What you Eat
First of all what are we?
Our body operates as a finely tuned machine dependant on the balance of various systems. The core components of these systems are atoms that combine to form molecules that combine to become cells. Therefore, we consist of a complex network of 60 trillion cells. Each type of cell having their own role and all of them interacting with each other in a specific physiological and biochemical way. Each cell will need oxygen and its own specific nutrient to perform its role.
The basic function of food is to keep us alive
Food contains nutrients, components that contribute to biochemical and physiological functions. The two basic functions of nutrients are to provide materials for growth and repair of tissues for the maintenance of our bodies and to supply our body with energy required to perform external activities as well as continuous internal activities. The fact is that to sustain life, the body has to be able to maintain its own internal processes. This is known as basal metabolism. So no matter what life brings us, illness or injury and no matter what we do or eat, our internal processes should absorb and neutralize the effects of these events and carry on. This is where we discover a third function of nutrients: to regulate all the processes needed for life. Nutrients are often grouped according to their chemical composition. The 3 macronutrients are fat, carbohydrate and protein. The 2 micronutrients are vitamins and minerals. Vitamins are organic nutrients found in foods and are essential in small quantities for both growth and good health. Chemically vitamins are made from the same elements: carbon, hydrogen, oxygen, and sometimes nitrogen or cobalt, but their elements are arranged differently and so perform different functions in the body. Although activities, habits and patterns of eating vary from person to person, everyone needs the same types of nutrients in roughly the same proportions. Here is the relation between nutrients and their function in the body and what type of foods supply them:
- Carbohydrates, fats and proteins - provide energy that is measured in calories.
- Proteins, minerals and water - provide growth and repair.
- Proteins, minerals, water and vitamins - control the body processes. As we discussed earlier, to sustain life the cell’s activities must be controlled and organized into a self-regulating and self-renewing pattern. This is where protein substances called enzymes fall into play. They control chemical changes (metabolism) that occur in cells. They regulate the building up reactions (anabolic) and the breaking down (catabolic) reactions that result in the release of energy. Enzyme activity is dependant on temperature and pH. The best environment for most enzymes would be around 25 degrees and in a neutral pH. However there are some exceptions; pepsin is present in gastric juices and functions only in acid conditions created by the stomach. Conversely, trypsin in pancreatic juice requires a slightly alkaline medium.
Our digestion is both physical and chemical.
The physical part involves breaking down large food particles into smaller ones. The chemical part involves the breakdown of larger molecules into smaller ones by enzymes to be able to pass into the blood stream to then be distributed to the cells. They help speed up the process so that digestion is completed in a matter of hours. Water is needed in this process to help split the molecules, this is called hydrolysis.
The digestion is divided in different stages.
It starts in the mouth where food is chewed to reduce the size of the pieces and saliva is secreted. It contains the enzyme amylase that starts the hydrolysis of the starchy food and releases glucose. When it gets to the stomach by peristalsis, it becomes inactive as it cannot tolerate the acidity of the environment.
20 minutes later in the stomach, pepsin is secreted and mixed with the hydrochloric acid forming the gastric juice. The food becomes chyme until pepsin turns proteins into peptones and rennin that coagulates milk. The chyme is released into the duodenum through the pyloric valve. This process lasts 6hours.
The main digestion occurs in the small intestine where 3 secretions exist: pancreatic, bile and intestinal. As they are alkaline, they neutralize the chyme. The pancreatic juice contains enzyme that help breakdown 3 main types of nutrients: trypsin and chymotrypsin for proteins, amylase for starch to turn into maltose and lipase to convert fat molecules into simpler substances. The bile contains salts that emulsify the fat. The intestinal juice contains maltase, lactase and sucrase to turn double sugars into simple ones. Erepsin continues the breakdown of protein into amino acids and dipeptidase into free amino acids. After 4 hours all the nutrients can now be absorbed through the intestinal wall vie the villi into the blood. Fatty acids will be directed into the lymph to be resynthesised as fat molecules.
After 7-9 hours after ingestion, all the nutrients that have not been absorbed in the small intestine pass through the ileo coecal valve and into the large intestine. There are no new enzymes but many bacteria that attack the waste and vitamin K and B and ammonia are synthesized. The main function of the colon is to dehydrate the mass until it reaches the rectum and faeces are formed. After 20 hours in the colon these materials will be passed out.
The nutrients that enter the blood stream will be transported to where they are needed. Blood consisting mostly of water, makes the transportation of fats difficult. So the emulsified fat gets coated with phospholipids then converted into lipoproteins. The heart pumps the blood in the capillaries where nutrients and oxygen diffuse into the surrounding cells. The waste goes into the veins with the co2 (removed by lungs) and removed by the kidneys.
Now that we understand how our body functions lets look at how our diet can affect us:
The phrase “You are what you eat” originated from Anthelme Brillat-Savarin in Physiologie du Gout, ou Meditations de Gastronomie Transcendante, 1826: “Dis-moi ce que tu manges, je te dirai ce que tu es.” [Tell me what you eat and I will tell you what you are]. As you can see, the idea that your wellbeing is related to your diet has long been noticed. It is now universally accepted that a balanced diet is essential to good health but the scientific principles behind this belief still remain overlooked.
With the years, with the changes of political and economical climates and the technological advances, our relation to food has altered. In the 19th century the concept of infectious diseases being caused by harmful bacteria was accepted and therefore measure were taken to prevent it. However the idea that disease could also be caused by absence of something was more difficult to grasp. The discovery of vitamins and minerals to cure deficiencies such as scurvy or rickets was great advance in nutritional science. This changed people’s attitude to food and established the importance of diet for maintaining health.
As we have seen our body needs an adequate amount of nutrients to maintain function. However these needs can change depending on temperature, exercise, illness, and age. If the balance of nutrients from different foods is not met, the body has to make concessions by restricting its function or developing storage for critical nutrients. There can also be a difficulty between supply and demand. As metabolism is a constant activity, the consumption should allow short-term storage of nutrients.
Fat is the most concentrated source of energy. The quantity of fat in the diet should reduce and the quality of fat should be directed at vegetable or fish oils rather than animal fat. Non starch polysaccharides (NSP) play an important role in a healthy diet. It is a source of bacteria for the colon that helps release fatty acids absorbed by the colon. It is a primary source of energy and adjusts lipid synthesis in the liver. Therefore increasing the consumption of unrefined carbohydrates i.e.: whole foods rather than processed foods. There should also be an adequate amount of vitamins and minerals in the diet but be careful about salt. Sodium chloride should be restricted as high levels can lead to hypertension. The guideline of a healthy diet has mostly been defined by the dietary reference values. In a way, an optimal diet would be one with the sufficient nutrients to avoid chronic diseases.
So what happens when our diet is unbalanced?
Our physical life consists of processing organic matter to produce energy, growth, repair and waste. How effectively we do this will determine our energy level, longevity, and wellbeing. Faulty digestion, poor absorption, inflammation and infections can originate from a lack of nutrients, stress at mealtime, the wrong kind of food and even mixing the wrong foods together.
As humans, we eat intermittently throughout the day. We are well adapted to eat high energy meals episodically. We tend to follow the eating-satiation-appetite-eating cycle that is driven by signals in the hypothalamus. Hormones, peptides and nutrients play an important role in this cycle.
There are different triggers to hunger
Initially, adipose tissue was considered simply as storage of fat that could be released for later energy supply. Now it has been discovered that adipose tissue also acts as an endocrine organ. One of the hormones secreted by adipose cells is leptin which plays a role in hunger signals. When the cell content of fat is high, leptin is released into the blood stream. It has been found that in most obese people, high levels of leptin are present but their body is resistant to it. This causes a constant appetite.
Other stimuli to hunger are boredom, comfort eating and inactivity. It creates a problem when people’s hunger starts to be governed by non appetite systems rather than the hypothalamic system as they interact with more complex mood and brain reactions. They become habits more difficult to control and only recognizing these triggers as distinct from appetite will help.
In the western world there has been a rise in obesity, diabetes, CHD and cancer which has been worrying the medical and nutritional science. It is known that these diseases come from a number of factors such as genetics, age, sex, weight, lifestyle (i.e. stress, exercises), smoking and diet.
The causes of obesity are various but it is accepted that a diet high in calories mostly due to high fat and sugar content is responsible. As we mentioned earlier, the eating behaviour is also important. Overweight people tend to underestimate the food intake. There is a noticeable link between the rise of obesity and the fall of exercise. When the physical activity drops below the energy expenditure necessary for appetite regulation an increase in food consumption occurs. Hormonal and psychological factors are also involved. Obesity leads to a higher risk of other diseases such as diabetes, heart disease, kidney failure, high cholesterol (gallstones) and arthritis due to increased loading on the joints.
Health can also be affected by the opposite problem. Excessive weight loss or anorexia can cause many deficiencies and lead to cessation of the menstrual cycle.
People may also develop intolerances to certain substances such as amines, which are present in wine, cheese, yeast and bananas. Tomatoes and strawberries can cause histamine release producing a rash. For certain people, some foods are harder to digest like lactose.
Milk contains sugar lactose, which can be difficult to digest when there is insufficient lactase to break it down in the small intestine. As a result lactose passes into the colon and converted into lactic acid by the bacteria and causes diarrhea. Food allergies are cause by an immune response to a substance called allergen. The allergen is often a protein or bound to one and recognized by antibodies. The most common reactive foods are milk, eggs, shellfish, nuts, wheat, yeast, coffee, preservatives and artificial colours. The best but most time consuming way to deal with these conditions is an elimination diet.
Celiac
Celiac disease is causes by malabsorption of certain foods leading to weight loss and mineral and vitamin deficiency. Patients are sensitive to the protein gliadin, which is part of the gluten contained in wheat and rye and to a lesser extent barley, rice and oats. It can originate from childhood or develop later on. The cause of the disease is unknown but may be due to a missing enzyme needed to break down gliadin. It will lead to irritation and destruction of the villi of the small intestine responsible for the absorption of nutrients.
Therefore the nutrients are excreted as fatty diarrhea. Children with celiac disease do not grow properly and may suffer from anaemia and rickets. It is much easer in our days to find gluten free products so the diet can be adapted to the patient.
Some people just decide to follow a specific diet such as vegetarian, pescatarian or vegan. These people will have to be careful with nutrient deficiency and adapt their diet to fulfill their body’s needs. This is where food combining method can be useful.
Food Combining
The term ‘food combining’ refers to those combinations of foods that are compatible with each other in digestive chemistry. Its aim is to aid the digestive process so that the nutrients are better absorbed. This will reduce the discomforts of indigestion and digestive tract irritation and diseases rather than using drugs to suppress the symptoms. Efficient digestion means better energy levels. By selecting compatible food combinations, the digestive task is lessened which allows more energy for other activities.
When eating two situations can occur: firstly, good digestion and nutrient enhancement or secondly, a form of self poisoning by decompositions of certain foods. For example, if carbohydrates are not digested, they ferment and produce poisons such as carbon dioxide, acetic acid, lactic acid and alcohol. When proteins are not digested, they putrefy and produce poisons such as ptomaine’s and leucomaines. This can lead to food intolerances. That is why helping our body as best as we can is important.
The guidelines for food combining are as follows:
- No starch and protein in the same meal. Starches need a more alkaline environment whereas proteins need a more acid one and the digestion of both these elements occur at two different stages.
- No fruit with other food. Because of its high sugar content, the fruit will ferment and cause digestive gas, flatulence and upsets. Eat fruit an hour before or an hour after a meal. Fruit taken between meals is an excellent snack. Taking everything into account, the concept of a balanced diet varies on each person depending on his or her environment, illness, age, genetic background and lifestyle. Nevertheless, the dietary guidelines for health published by independent scientific committees in many countries are now very similar. High fruit and vegetables and low saturated fat and salt diets offer benefits for preventing many diseases (i.e.: diabetes, heart disease, strokes and cancers). Theses guidelines although designed for certain population targets, are useful benchmarks for individual eating habits. We now have a lot of research that suggests that a balanced diet and physical exercise are at the base of a stable and healthy body.
The world health organization has defined health as a state of complete physical, mental and social well-being and not merely the absence of disease. This is why our diet should not just be considered merely as a nutrient intake but also a pleasurable activity. Health is not just eating the right foods but our attitude to eating, approach to life and the right balance in our lifestyle. Stress and anxiety can affect our well being much more than nutrients. Thus, social and cultural aspects of foods and meals, taste, texture, aroma and political conditions of food production can all contribute to a healthy living.
