Basic Food Chemistry

Nutrition Chemistry in (VERY) Brief: Have you ever heard this line in a sci-fi film: We are carbon-based life forms! The human body requires six types of nutrients. The term “organic” means that a substance contains the element carbon in a certain relationship to hydrogen (methane, the simplest organic compound, though not edible, is shown above).  This is a different meaning from “organically grown” which means that the farmer is paying careful attention to avoiding synthetic pesticides and fertilizers, among other criteria. Three of the six nutrients are organic substances we need for calories: carbohydrate, protein and fats.

Carbohydrates are organic substances with the elements carbon, hydrogen and oxygen in the ratio 1:2:1. For example, the important sugar in our blood, glucose, is written C6H12O6. We metabolize the glucose and transform it to energy, CO2 and H2O in a process called cellular respiration. We are always breathing out the CO2 and water produced. The amount that a substance will affect the blood sugar is called the glycemic index, and it is compared to the effect of eating glucose. The more refined and sugar-like a substance is, the greater the effect on the blood sugar, which is why fructose and sucrose have large effects, and proteins and fats have small ones.

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You can raise your blood sugar almost as quickly with refined starches that are the bulk of white wheat flour, white rice and other grains. These starches are polymers (chains) of glucose molecules, and are converted to blood glucose with just one or a few enzymes. The diagram above shows four glucose molecules (roughly hexagonal) bonded together. The brackets around one of them indicate that this pattern repeats a certain number of times, usually more than a thousand.

A number of diets such as the pH Miracle and Elimination Diets suggest not eating refined starches because they are converted to glucose so quickly. Others, like the Paleo Diet, suggest not eating any grains. Whole foods like vegetables and fruits contain carbohydrate, but the sugars will be present with some fiber and some protein, not to mention vitamins and antioxidants. Grains and legumes, most of which need to be cooked, will be starchier, which is partly why they are more filling. They can be excellent sources of protein, fiber and some fats.

Fats are slowly metabolized to sugars, requiring many enzymes, which is why you rarely hear anyone suggest eating them for quick energy. They are essential for their role in hormones, cell walls and antioxidant production, which is why a fat-free eating plan is dangerous for any length of time. Most people have heard the words “essential fatty acids” and know they are important, but will sometimes be buying fat-free products at the same time. I believe it’s worth spending a little more money to use the healthiest fats available, focusing on whole sources of omega-3 fatty acids such as flax seed, walnuts, wild salmon, grass-fed dairy, and eggs from pastured or flax-fed chickens.

Proteins can be converted to sugars but usually are not; this requires many enzymes and thus a lot of energy. Your proteins are converted to blood sugars in the case of very low-carbohydrate diets; this process carries the risks of ketosis and gout, which is why Dr. Robert Atkins advised people to stay on his strict diet for a relatively short period of time. The GAPS introduction diet also needs to be carefully planned to avoid ketosis by including enough vegetables to balance the high protein content.

Vitamins are important organic substances, but provide no calories. Vitamins are needed for cells to convert the other organic substances to energy, often being substances that allow your digestive enzymes to function. This is why you should never consume vitamins without food. The last two nutrients are minerals and water. Minerals provide electrolytes and the materials for bones among other essential roles. Water not only helps carry nutrients around the body but is also taken up and given off in metabolism.


Our Personal Eating Research Project

The Main Idea:  During the seventeen years I taught high school chemistry, I often joked that I could have taught a lot of it in a kitchen. Well, everything except the explosions. My students, though, were fascinated (at least they said they were!) to learn what was behind food labels and connect the chemistry with their health. Thanks to the students at the Honolulu Waldorf School for their wonderful questions over all those years.

The Body as a Research Project.

Every day we conduct biochemical research on our own bodies. Most of the time, though, we don’t collect data. Rather, we eat and run and hope it’s healthy, struggle to decide about low-fat or low-carb, or eat what’s handy. In our earliest years we trust others to do the shopping, cooking and feeding. Our organs and enzymes faithfully process what we eat and provide us with the energy and nutrients in the food, and will do so until they get worn out with age or illness. But we can always work to become more conscious of how we are feeling after we eat certain foods, to learn about why this is so, and to choose to change or not.

Why the name un-chemical? Often people will tell me they don’t eat any chemicals, but this is actually impossible. Food is a set of chemicals – which is why the field of “food chemistry” exists, and covers everything from basic carbohydrate, protein and fats to vitamins, probiotics and pros and cons of GMO technology. If we take time to understand the chemistry we can gain some control over it and avoid the refined and toxic chemicals that may be part of the food available to us.

Some food metabolism is well understood, but how to apply it is under great debate. Witness the number of nutrition blogs, weight loss websites and diets! There are passionate advocates of vegetarianism, raw foods, paleo diets, pH diets and everything in between. If you are here, maybe you wonder if they have anything in common, or how to start simply in changing how you eat. Each issue of this blog will contain one or two diet resources, the chemistry behind an issue, a recipe that puts it into practice, and some reading to pursue.