About: This is to bite into a better understanding of the food we eat. Of what goes down the hatch, through our digestive tract, and exits peacefully-and sometimes with the sounds of thunder, and gas to light up the world. And perhaps eat with wisdom to live another day. We have learnt about all of them, in bits and pieces, at school, and this is a grown-up, graduate view of the fundamentals, without much of scientific jargon. This is also to bust certain myths-especially about Proteins and Cholesterol. You can unfasten your belt and eat into the meat of the matter. We are doing this together.

The human body needs to be fed with nutritive food for it to be kept well-oiled, to function efficiently, and keep us alive; with the least amount of destabilising forces-diseases. We have come a long way from the hunter-gatherer mode of living, when we obtained our daily bread as foragers-running all over the place- to the present day method of producing food by quiet farming and clever cultivation. Now, the food we require arrives on our table from every corner of the world, labelled and packed with names of the nutrients, the energy they provide, and much more-if we dare to thoroughly read the Lables stuck on them.

When man first learnt to make and use Fire, things changed like never before: cooking was born, which gave us all kinds of benefits such as, killing toxins in the food, improving taste, making tough substances easy to digest…and the kind. Cooking freed up a lot of time for us humans, while other animals in the Kingdom spend as many as seven hours a day just chewing food-wish they could learn to cook?

We do not need to eat constantly to survive. Unfortunately, we eat more of less constantly anyway-and that’s another big story in itself. The objective, after all that chewing is to mix it with enzymes in the saliva, and other ‘juices’ down the tract, which the body itself makes, to digest the food and break it down into a form the body can handle. And provide energy for us to walk, run, and dance, and fight each other and other kinds of animals, on dear Planet Earth.

To drive on the road ahead, here are a few science basics we need to refresh ourselves about. Everything in the Universe, including us, is made of Atoms – the smallest unit of matter with a central dense nucleus of protons(and neutrons) and a cloud of electrons spinning around. And going even higher, we can say we are all made up of ‘star dust’. What we call ‘element’ is made up of only one kind of atom – elementary? There are about 118 known elements, but our body is constructed from just 59, and 6 of them account for 99.1%. When two or more atoms are chemically bonded they form a molecule, which can be of the same element or different elements. A compound is a molecule made up of two or more different elements chemically bonded in a fixed ratio. Our body is built with such compounds.

Moving back to Food, let’s strip-down it down, peel-off the layers and see it gloriously naked.

The fundamental components of the food – call it nutrients- we eat, is divided into two broad categories, 1-Macronutrients: Water, Proteins, Carbohydrates, and Fats, and the 2-Micronutrients: Vitamins, Minerals, and elusive Trace Elements. The macro food is required in larger quantities; the micro food is required in smaller quantities and is essential in keeping us living the good life. Let’s digest them one by one. I am leaving-out the water we drink, and the air we breathe, which need space of their own. Let’s drink, and smoke to that!

PROTEINS

Proteins are large, complex molecules that are indispensable for life. A fifth of our body weight is made up of them. They are the ‘building blocks’ of our body and also the hard-working craftsmen- mending and repairing wear and tear. Basically, Proteins are long chains of tiny building blocks called amino-acids. Think of them like different coloured beads strung together into a beautiful necklace.

Proteins are made from just 20 amino acids-organic compounds-even through hundreds of amino acids exist in nature, which can do the job just as well. It is a mystery why evolution has married us, for life, to just these 20. And we simply cannot divorce them! And the best part is, we break down all the proteins we consume only to reassemble them again, into new proteins. LEGO toys of the body?

Eight, out of the twenty, amino acids cannot be made -synthesised-in the body and we must find and consume them from the outside world. And the factor to consider is their digestibility. In general, proteins from uncooked vegetable foods are less digestible than those from animal foods. Hence, cooking is awfully important. Glad we know how to start a fire.

There is a never ending debate about Plant-based proteins and Animal-based proteins: which one is best for us. Animal proteins are typically complete proteins-contain all essential amino acids-with very high digestibility and bioavailability. Plant proteins are often incomplete: missing or low in one or more essential amino acids, but we can achieve complete profiles by combining different sources, e.g., rice & beans. Animal World or Plant World, we can achieve great protein balance, but we need to work harder and wider on the plant side.

Common protein foods are: eggs-with near-perfect amino acid make-up; fish-salmon, sardines, mackerel; meat-chicken, pork; organ meat-liver, heart, kidney. On the plant side we have soy products, lentils, chickpeas, nuts & seeds, almonds, peanuts, beans, brown rice, legumes, pumpkin seeds, and others.

CARBOHYDRATES

Carbohydrates are compounds of Carbon, Hydrogen, and Oxygen, which are bound together to from a variety of sugars: glucose, fructose, maltose, sucrose, deoxyribose(the stuff found in DNA), and so on. Some of these are chemically simple such as monosaccharides, some are complex known as polysaccharides, and some in between known as disaccharides. Carbohydrates are basically a class of energy yielding substances and almost all of them come from plants, with one exception: lactose-from milk. Foods like cane sugar and table sugar are simple carbohydrates, and those like starch are a complex. These are completely digested by the body, and the end product is sugar-glucose-which is absorbed and metabolised to provide the energy required for all body functions.

Besides the digestible carbohydrates of sugar and starch, there are other non-digestible carbohydrates like cellulose, hemicellulose, gums, pectins and lignins ‘legally designated’ as ‘Dietary Fibre’. They are necessary superfluous food, as most of them are not digested and sent marching out, through the stools. We do not have the enzymes to crack and break them down, though the bacteria in our gut can feast upon many of them. Why then the Fibre? They facilitate the process of digestion and elimination of waste. The contraction of muscular walls of the digestive tract is stimulated by fibre counteracting the tendency to constipation. They cause food to linger in the stomach for longer periods, helping wholesome digestion. And to alleviate hunger and prolonging the feeling of satiety. When food without fibre is consumed it gets processed too quickly, leading to ill effects such as spiking in blood sugar. Fibre acts like a sponge, absorbing and holding water, making us feel full, with a lesser quantity of food.

Back to some definitions: Constipation is a condition wherein stools are hard, dry, or painful to pass and leave a feeling that not all stools have passed. Enzymes are biological catalysts: molecules that accelerate chemical reactions without being consumed or permanently altered themselves. They are mostly proteins.

Common carbohydrate foods: whole grains, legumes, fruits, starchy vegetables, and some dairy. Others in the whole grain family are oats, brown rice. And Legumes-beans, chickpeas, peas. Starch Vegetables-potatoes, corn, and Fruits- Bananas, Apples, berries, oranges, mangoes, melons, are other sources.

FATS

Fats are also made up of Carbon, Hydrogen, and Oxygen, but in different proportions – in a more clever way than the ‘serious looking’ carbohydrates – making it easier for fat to be stored in the body. Helping us get fat? Looking at it in another way, fat is a concentrated source of energy, and it supplies per unit weight more than twice the energy than can be supplied by proteins or carbohydrates.

Words such as Oils, Fats, and Lipids are used interchangeably to describe Fats. Broadly, we use the term Oils for liquids, and Fats for solids at room temperature. And we talk about oil or fat in relation to the food we consume; and Lipids while talking about them inside the body. To give more meaning to Lipids, think about Neurons- the cells that make up the central nervous system of the body- they have a layer of lipids called the myelin sheath, which protects the delicate nerve cells and helps electrical impulses travel quickly between them. If this sheath is damaged, we can go crazy. About 60% of our Brain is made up of fat. Hence, we have to make sure we treat fats with respect.

Oils and fats are made up of units called fatty acids, like bricks in a wall-much like amino-acids are the building blocks of Proteins. Fats are broadly classified as: Saturated Fats, mostly solid at room temperature-predominate in animal based fats, and Unsaturated Fats-mostly liquid at room temperature- predominate in vegetable based. Fats derived from vegetable sources provide what is known as Essential Fatty Acids, which has Vitamin(that’s coming up ahead) like functions in the body.

There is another kind of fat we often read about: Trans Fats, also known as hydrogenated oils, which are artificially produced. They are created when vegetable oils, typically in liquid form, are processed (hydrogenated) to become solid fats. They were touted as a healthy alternative to butter or animal fat, but we now know the opposite to be true. To put it bluntly, Trans fats are essentially a form of slow-acting poison. Do not look in their direction.

Then there is Cholesterol, a waxy, fat-like molecule that is vital for life and present in every cell, giving it its structure through the cell membranes. It also enables production of certain Hormones and Bile Acids-to digest food, and for synthesis of Vitamin D. The Liver, the largest organ in the human body, produces almost all the cholesterol required by the body. Other body cells produce some and anything else required is from the food we intake. Cholesterol is not strictly classified as a fat. And it is not found in plants. Cholesterol has earned a bad name, for the wrong reasons, and I am out to pin some medals on its chest.

Getting to the fat of fats, something called Triglycerides makes up 95% of the fat we eat. They consist of one glycerol molecule attached to three fatty acid chains. In the body, they store unused energy and release them when needed. The remaining 5% consists of other types of Lipids. When you see ‘total fat’ on a nutrition label, it’s mostly triglycerides. The other lipids are present in much smaller quantities and often have important roles.

When fats are broken down in the body, they team-up with cholesterol and proteins in a new molecular avatar called Lipoproteins, which act like delivery trucks for distributing fats and cholesterol through the bloodstream. Fats cannot dissolve in the blood, hence they need to be carried by this cleverly designed transport mechanism. Lipoproteins consist of cholesterol and triglycerides in equal proportions.

Fats in the food that we eat are primarily digested in the small intestine and converted into fatty acids, among others. Intestinal cells reassemble them again into triglycerides and hitch them to cholesterol to form the lipoproteins. And due to their low density-when first formed, innocently- they are called Very Low Density Lipoproteins (VLDL). Fats made in the liver are then loaded on to the VLDL truck and sent for circulation in the bloodstream, delivering triglycerides and cholesterol to all parts of the body. As the VLDL loses triglycerides, the lipid-to-protein ratio changes, becoming denser and the VLDL becomes Intermediate Density Lipoproteins (IDL). As the process continues and triglycerides and cholesterol are delivered to further cells in the body, IDL is gradually converted into Low Density Lipoproteins (LDL). This LDL returns to the liver to be reloaded and sent again for circulation. The liver then sends High Density Lipoproteins (HDL), that it produces, along with some support from the small intestine, to collect any ‘spilled’, remnants, or excess cholesterol and triglycerides and bring them back to use for the next circulation, or for disposal. We can call HDL a scavenging or recovery truck. They do it by a process called Reverse Cholesterol Transport. Its structure, especially its high protein-to-lipid ratio enables this function, making it denser and smaller than LDL. Talk about sending the good guys to catch and jail the bad guys – that’s what ‘Sheriff Liver’ does in the Body County.

Keep in mind the fact that the Liver is the ‘super-man’ of the body performing over 500 mighty, vital functions. And it has this insane ability to regenerate itself: if up to 70% is damaged or surgically removed, it can grow back to its full size and function within weeks. Wow! We never look under the hood, do we? And how clever! The home lizard must be envious: it easily lets go of its tail -to sidetrack a predator-and then cooly grows it back. What the lizard does externally we do internally-but for healthier reasons!

Most of the cholesterol in our bodies is locked up in our cells where it is doing useful work. Just a small part, about 7%, floats around in the blood, out of which one-third is good and two-third is bad. Though we call LDL, bad cholesterol- the bad guy- and HDL good cholesterol- the good guy-Cholesterol is not fundamentally evil as we tend to think about it. It is vital for a healthy life and the trick is to maintain it at a balanced level. One way is to eat a lot of Fibre, which contains no energy or vitamins, but helps to lowering cholesterol and slows the rate at which sugar gets in to the blood and then turned into fat by the Liver.

The best food sources of fat are unsaturated fats and a limited amount of saturated fats. Some are, Avocados, Olive oil, Nuts- Almonds, Hazelnuts, Walnuts, Peanuts, Seeds-Pumpkin, sesame. Others-Canola oil, Peanut oil, Olives, Soyabean, whole Eggs, Dark Chocolate.

VITAMINS

Vitamins are simply organic compounds- from things that are or were once alive, like plants and animals. They are quite a new concept, becoming famous only in the 1920s, when naming them in a kindergarten style alphabetical order began. Somewhere down the line numerals stuck to them. Now we are swarmed with, A, B, B1, B2,…B12, C, E, D, K… etc.

Vitamins play a vital role in utilising the proteins, carbohydrates, and fats we intake as food. They mostly act as co-enzymes. Our body uses vitamins to convert food into energy, build and repair tissues, support immune function, enable nerve signaling, maintain vision and bone health, among other functions. Unlike carbohydrates, or proteins, vitamins are needed only in tiny amounts, but without them, normal metabolism stops or becomes inefficient, leading to deficiency diseases.

Vitamins do not provide energy or building blocks themselves, instead they are the tiny ‘keys’ that unlock and drive the body’s various compartments of the core metabolic machinery.

Vitamins are broadly classified as Water Soluble and Fat Soluble. Water soluble are not accumulated in the body and are easily excreted, while fat soluble ones are stored. B-Complex Vitamins and Vitamin C- Ascorbic Acid are Water Soluble, while Vitamins A, D, E, K are Fat Soluble.

Common Vitamin Foods: whole, minimally processed foods like fruits, vegetables, leafy greens, nuts, seeds, legumes, whole grains, lean proteins, and dairy or fortified alternatives. Citrus fruits (oranges, grapefruits), Strawberries, Kiwi, Bell peppers (red or green), Broccoli, Tomatoes, Potatoes.

MINERALS

Minerals are inorganic, and come from soil or water. Let’s call them the cousins of Vitamins. Altogether there are about 40 of them that we must get from our foods because we cannot produce them in the body.

Minerals perform critical structural and regulatory roles. Unlike vitamins, minerals often serve as building blocks, electrolytes, and catalysts. E.g., Calcium, Phosphorus, Magnesium build and maintain bones & teeth (99% of calcium is in the skeleton); provide rigidity and strength. Iron is the core of haemoglobin-carries oxygen in blood- and myoglobin-in muscles; essential for energy production.

Common Mineral Foods: this is Home Work No-1, search them out and keep them.

Dairy, canned fish with bones, leafy greens, fortified plant milks and orange juice, and almonds, are some sources.

TRACE ELEMENTS

Beyond the Big THREE and the smaller TWO of Vitamins and Minerals, completing the list, a large number of elements are required in trace amounts for a wide range of functions, to keep the body in ‘top condition’. They are mainly, Iodine,Zinc, Copper, Chromium, Manganese, Molybdenum, Fluoride. And finally, there are many unknowns, such as Selenium, Cobalt, Silicon, Arsenic, Nickel and Vanadium, which use is yet to be established. For sure we know arsenic is a toxic element and whether it indeed has any nutritional value is yet to be discovered – at our peril?

Common Trace Element Foods: This is Home Work No-2, we have to hunt them down. I suggest you consult ‘Doctor Know’ and perhaps a Bounty-Hunter too.

The problem with the micronutrients of Vitamins, Minerals, and Trace elements is that the risk of taking in too much is a great as the risk of taking too little. To give examples: Vitamin A is needed for vision, healthy skin and fighting infections. Eggs and dairy products have a lot of them, hence easy to obtain. The recommended daily level is 700 micrograms for women and 900 for men; the upper limit for both is about 3000 micrograms, and exceeding that ceiling can become risky. Vitamin A is fat-soluble, so excess gets stored in the liver and can accumulate, leading to acute or chronic toxicity. Iron similarly, is vital for healthy red blood cells. Too little iron, and we become anaemic, but too much is toxic, leading to lethargy. Too much of iron can accumulate in our tissues causing our organs ‘literally to rust’.

Armed with this understanding – and after testing the state of parts under the body bonnet-we must challenge ourselves, our Spouses, Partners, Cooks, Doctors, Dieticians, and Nutritionists… to eminently balance the food we eat. Spare parts are not an option-with exceptions. We are not House Lizards.

Ultimately, I can sign off saying, “We Built This Body”.

Bibliography: The Body, by Bill Bryson; Craft your Wellness, by Dr Gauri Rokkam; Nutritive Value of Indian Foods, by C Gopalan, B V Rama Sastri,and S C Balasubramanaian, Indian Council of Medical Research, National Institution of Nutrition, Hyderabad. These are excellent reads with lots of ‘nutritive value’-for the brain.