I think, of all the various aspects of understanding our health, nutrition is the most confusing and misunderstood. It’s a complex topic requiring some basic knowledge of organic and biochemistry, as well as understanding of a good bit of anatomy and physiology. And since diet is one of the most easily manipulated factors of our self care, there is no end to experts, pseudo-experts, and outright charlatans telling us what to eat, when to eat, etc. Quite bewildering!
If you’re not planning to sign up for chemistry, human physiology, and nutrition classes at the local college, there are still some great resources to help make sense of all this information. Finding reliable websites with factual information rather than speculation and promises of perfect health if you only buy this or that product takes a bit of research. One good tip for that is the old maxim, “If it sounds too good to be true, it probably is.” If you come upon a site quoting research that sounds a bit overreaching or quite different than what others are publishing, do a search and look for independent corroboration of the claims.
I’ve found some sources that are reasonably reliable on the web. The US government nutrition website has a wealth of information and links to other resources about specific topics at Nutrition.gov. If you aren’t sure you trust the US government, you can try the Canadian alternative here. One site I use frequently to look up nutritional data on specific foods is NutritionData. It’s more of a commercial site, connected to Self magazine, but is a handy resource. The Harvard School of Public Health has put together a very nice site called The Nutrition Source.
I’ll give a brief explanation of basic nutrition principles here, but see the sites above for more detailed information. Or you can go sign up for those college courses! I found them very informative and enjoyable myself.
When we look at foods, they are constructed of 3 basic types of molecules: carbohydrates, fats, and proteins. Alcohol constitutes a fourth type that is important to study of health and nutrition. These four molecule types are the main types our body has adapted to convert into energy. Carbohydrates are generally divided into categories of simple and complex. Simple carbohydrates are sugars such as glucose, fructose, lactose, and sucrose (table sugar), to name a few. Complex carbohydrates are starch, found in grains and potatoes. When speaking of foods, carbohydrates can refer to either the actual carbohydrate molecules in the food or to a food that is rich in carbohydrates (sometimes called “carbs”). Each gram of carbohydrate has 4 calories. Calories are a unit of heat. One calorie is the amount of heat it takes to raise the temperature of one gram of water one degree Celsius at normal atmospheric pressure. The calories we refer to in foods are actually kilocalories which are 1000 of the small calories. This is sometimes abbreviated kcal.
Another type of food molecule is fat. These molecules are triglycerides, a combination of glycerol and fatty acids. These compounds contain more energy than carbohydrates, making them an efficient way to store energy in the body. Each gram of fat has 9 calories. Common fats are oils such as olive oil or canola oil, butter, and lard. Fats are referred to as saturated, monounsaturated, or polyunsaturated. This has to do with how many of the carbon atoms in the fatty acids have hydrogen atoms attached to their free bonds. That’s kind of technical and if you are interested in that level of information click on the link at the beginning of this paragraph. For practical purposes, saturated fats are more solid at room temperature, like butter. Saturated fats are found mainly in animal products (meat, milk, etc.) and tropical oils like palm oil or coconut oil. Mono- and poly-unsaturated fats are more liquid and this includes most oils such as vegetable oil, fish oil, etc. Avocado, canola oil, and olive oil are rich in monounsaturated fats. Corn oil and safflower oil have more polyunsaturated fat. In general, less saturated is better.
Cholesterol is a different type of molecule found in animal fats that is a structural component of cell membranes. Our bodies make cholesterol, so we don’t need to eat it to survive. We are told to limit cholesterol to protect our cardiovascular health. The way to do that is limit animal products such as meat, high fat dairy, and eggs.
Proteins are found in animals and plants and make up structural components and some hormones. Proteins have 4 calories per gram and are made up of chains of amino acids. When they are digested, they are split into the individual amino acids which are then broken down further for energy or used by the body’s cells to create proteins vital to our structure and function. Protein rich foods include meats, fish, dairy, grains, legumes, and nuts.
The alcohol that people drink is ethanol. It has 7 calories per gram, so like fats it is pretty dense, calorically speaking. The body is able to convert alcohol to energy, though not as efficiently as carbohydrates and proteins. Alcoholic beverages are rated by proof, with each proof being 0.5% alcohol. Thus 80 proof vodka has a concentration of 40% alcohol. Beer and wine are labeled with their alcohol by volume (ABV) with beer typically running 4 to 6% and wine 9 to 16%.
That’s a lot of information to “digest.” Next time I’ll talk more about dietary recommendations and the micronutrients.