Nutritional minerals in food are elements, also known as atoms, and you can find them in the Periodic Table of the Elements (below).
Elements are made up of protons and neutrons that reside in a central nucleus. They also have electrons that orbit the nucleus in shells similar to the layers of an onion; also kind of like satellites that orbit the earth at different altitudes.
The number of electrons in the outermost orbit of the atom is what determines how stable they are and how they combine with other atoms to form compounds.
A calcium atom has 20 protons which is what makes it calcium. Similarly oxygen’s 8 protons and carbons 6 protons is what gives them their unique identity. The number of protons in an atomic nucleus is what determines the element.
Vitamins are not elements, they are compounds; meaning they are made up of a collection of different atoms. For example, vitamin C is made up of 8 hydrogen atoms, 6 oxygen atoms and 6 carbon atoms.
The Essential Minerals in Food!
There are 12 essential minerals that we know the body needs to stay alive and functional. There is another 7 that we think are important to human life but the proof has not been firmly established.
As with vitamins, minerals have very specific and well defined multiple roles to play in the workings of our body. Just from TV commercials, we should all be somewhat familiar with calcium or at least its effects if we don’t get enough.
Three Classifications of Minerals in Food
Minerals in food that are used by the human body for nutrition can be classified into three groups.
- The first is six minerals that are stored in large quantities in the body. They are Sodium (Na) and Chloride (Cl), Potassium (K), Calcium (Ca), Magnesium (Mg) and Phosphorus (P).
- The second group is seven minerals in food that appear in trace amounts but whose importance has been well established. They are Iron (Fe), Zinc (Zn), Copper (Cu), Iodine (I), Floride (F), Selenium (Se) and Chromium (Cr).
- The third group are minerals in food, also in trace amounts, that have been proven to be important in lab animals but whose role in human nutrition and health has not be firmly proven. They include Cobalt (Co), Molybdenum (Mo), Manganese (Mn) and Nickel (Ni) plus a few others.
The nutritional use and source of these minerals in food are briefly discussed below according to their group classification.
There are 17 recognized essential minerals however there are several more minerals in food that may be important or may even be harmful as toxins, cadmium and mercury for example.
17 essential minerals are itemized below.
Group One: Minerals in Food Stored in the Body
Calcium (Ca), provides the major part of the matrix structure of bone and for most people, that is its only purpose. There is much more to the calcium story. It is needed for coagulation of blood, it is vital for the excitability (activation) of nerves, allows the muscles to contract which means that the heart won’t pump without calcium and it is a messenger for many secretory processes in the digestive system.
It is also required for maintaining the integrity of the cell’s membrane and keeping junctions between cells intact which is critical for absorption. These are all highly important functions and thus serum levels of calcium are precisely controlled. If external sources of calcium are not available, the body will requisition calcium from the bones.
Natural food sources include dark leafy greens, broccoli, dairy products and yogurt (no surprise), oranges and asparagus. Absorption is the key to efficient utilization of calcium and requires vitamin D and a parathyroid hormone to ensure good absorption. Calcium is one of the most important of all minerals in food but it is important to know that it is absorbed better in some foods than others. Calcium in milk and diary products are easily absorbed but not so much in the green vegetables.
Phosphorus (P) and Potassium (K):
These essential minerals keep a couple of things in balance. Without phosphorus, the acid-base balance, called the pH factor, in our body would be out of kilter and our nerves, muscles and kidneys wouldn’t work right. Without potassium, the water level in the body would be out of balance and couldn’t regulate blood pressure. Phosphorus is found in most foods but dairy products, meat, and fish are particularly rich sources. Bananas have a reputation as being rich in potassium but in reality they are pretty far down the list. Foods containing a much higher content of potassium would be soy flour, fresh apricots, tomato puree, figs, raisins and wheat bran.
Magnesium (Mg) is a vitally important mineral in that it plays a part in muscle contraction, bone mineralization, energy metabolism and the transmission of nerve impulses. If that weren’t enough, about 300 different enzymes depend on magnesium to perform their duties; particularly those that make adenosine triphosphate (ATP), the fuel that powers our body and those that assist in the construction of DNA and RNA.
In relation to bones, about 50% of our body’s magnesium is stored in our bones with the rest residing in the cells of tissue and organs. Magnesium and Calcium work together as partners in that Mg enhances the absorption of Ca in the intestine. This wonderful mineral has also been used to treat or prevent cardiovascular disease, diabetes and hypertension.
In general, green vegetables (those containing chlorophyll) will contain magnesium; for example just a half cup of cooked spinach contains 66mg of Mg. Wheatgrass is getting a lot of attention lately (see link above) in that it contains more than 90 minerals, including high concentrations of the most alkaline minerals such as potassium, calcium, magnesium, and sodium.
If you are a “juicer” consider adding a teaspoon of wheatgrass powder to your concoction. Most people do not get enough Mg in their diets so supplementation is called for in many cases. If taken as a supplement, an upper limit of 350 mg/day has been established however, it is difficult, if not impossible, to get a magnesium overdose from food.
Sodium really plays the field; so important in so many ways. It’s a key regulator in our bodies…regulates water balance, regulates flow of substances in and out of cells, and regulates blood pressure, electrical nerve signals and muscle contraction. Most of our sodium comes from normal table salt (NaCl); about one-third from the salt shaker. Another third we get from processed foods and the last third from the food itself.
pHion is the category leader when it pertains to pH balancing of the body.
Group 2: Trace Minerals in Food That are Proven to be Important
Copper (Cu) is one of the more important trace minerals in food. It is needed by enzymes that aid the absorption and release of iron from tissues and thus is important for hemoglobin production. Other uses include maintenance of blood vessels, tendons and bones; proper working of the central nervous system; pigmentation of hair and normal fertility.
Large amounts of copper reside in the liver, brain, heart, spleen and kidneys.
Copper is obtained from organ meats, shellfish, lamb, pork, tofu and nuts. Whole grain cereals, dairy products, lentils, mushrooms, dried beans, canned tomatoes, curry powder and chocolate are also great sources for copper.
Chromium (Cr) is a cofactor of insulin meaning that it has to be present in order for insulin to do its job. It is abundant in the soil as chromite which is absorbed by plants but the form or availability of Chromium in specific plants is not generally known. Spices and brewers yeast contain the highest concentrations and meat, dairy products and eggs are also good sources.
Fluoride (F) makes us smile! It is needed for the growth of bone and enamel which protects us both from brittle bones and dental caries (cavities). Since most food is low in flouride, many communities fluoridate their municipal water supply. A few foods that are higher in flouride include tea, grape juice, sardines, fish and chicken.
Iodine (I) is familiar to most of us as that purple liquid that we put on cuts. But when we think iodine, we should think thyroid since it is primarily used for the production of thyroid hormone.
The thyroid gland, kidneys, salivary and gastric glands all compete for free iodide. In fact the thyroid must trap about 60 ug of iodide per day to maintain thyroxine levels. Thyroxine is the major hormone excreted by the thyroid and function to increase the number and activity of mitochondria in cells by binding to the cells’ DNA, increasing the basal metabolic rate.
Thyroxine causes an increase in the rate of carbohydrate metabolism and a rise in the rate of protein synthesis and breakdown. Thus a deficiency of iodine can lead to major problems with our metabolism.
When it comes to minerals in food, the iodine content of food (and water) is related to the iodine content of the soil. The primary food source is seafood but most people get adequate intakes of iodine from using iodized salt.
Iron (Fe), out with old, in with the new. Did you know that every cell in our body has a programmed life span? The medical word for it is “apoptosis”. Now forget it and never use it again. When the cell completes its job, it dies. Wouldn’t it be a good idea to be able to replace all those dead cells. That’s where iron comes in.
Blood cells are pretty important to our well being and iron is critical to making new red cells and white blood cells in the immune system. Iron also promotes normal brain function. Hmm, maybe Congress could use a little more iron.
There are two forms of dietary iron known as heme and non-heme and without going into detailed explanations, let’s just say that the importance of which it is relates to absorption by the body. Heme iron is found only in meat, fish and poultry and is absorbed much more easily than non-heme iron, mostly found in fruits, vegetables, dried beans, nuts and grain products.
Selenium (Se) is one of the essential trace minerals in food and is a component of the enzyme glutathione peroxidase. As such it acts to reduce hydrogen peroxide and protect membrances from oxidative damage. Selenium also forms complexes with heavy metals and can protect against cadmium and mercury toxicity.
It has received a lot of attention for the prevention of prostate cancer but the evidence shows that the apparent benefit is limited to men with low basal plasma selenium and/or those who smoke.
An upper limit of 400 ug per day has been set to avoid the possibility of selenium toxicity.
The best sources are Brazil nuts and kidney although neither are common foods in most diets. Moderately good sources are fish, shellfish, organ meats and whole grains while fruits and vegetables are poor sources of selenium. Organic selenium minerals in food are absorbed best while inorganic is poorly absorbed. If supplementing with selenium, be sure to use a brand that is plant sourced.
Zinc (Zn) is a powerhouse in the immune system and is present in more than 2000 enzymes involved in the digestive process. Research shows that a zinc deficiency causes a rapid decline in antibody and cell-mediated immune responses in both humans and animals.
Seafood enriches the diet with a good source of zinc—an important element for immune health. World Port shown in the banner above is a good source of seafood delivered to your door. It is a division of Omaha Steaks after all.
Zinc mainly comes from protein rich foods such as beef, lamb, pork, crab, turkey, chicken, lobster, clams and salmon. Vegans have to get their zinc from milk, cheese, yeast, peanuts, beans, whole grain cereals, brown rice, whole wheat bread, potato and yogurt. Even so, vegans would be wise to supplement for adequate zinc intake.
Group 3: Trace Minerals in Food Whose Importance Has not been Clinically Proven
Cobalt (Co): keeps the red blood cells healthy and helps avoid anemia. Cobalt, like Copper, is obtained from whole grain cereals, shellfish, organ meats, fruits, leafy green vegetables, legumes, nuts and poultry.
Manganese (Mn) and Molybdenum (Mo)
Manganese (Mn) and Molybdenum (Mo); these two work on various aspects of metabolism, which is making sure all the chemical reactions in the body work like they’re supposed to. Manganese helps process blood sugar; makes DNA, connective tissue, cholesterol, and energy to help with brain function. Molybdenum helps fat burn and works to keep the liver, kidneys, teeth and bones healthy. Manganese and Molybdenum both come from green leafy vegetables, tea, whole grain cereals, beef liver, blackberries, lima beans, pinto beans and sweet potatoes.
Nickel (Ni) is a trace metal whose functions in the human body are not very clear. Nickel functions to activate or inhibit enzymes containing other elements and is involved in the production and action of some hormones. Some possible health benefits include support of growth, healthy skin and bone structure. It influences absorption of iron and may also play a role in production of red blood cells. Nickel is found in oatmeal, dried beans and peas, nuts, and chocolate.
Recommended Mineral Allowances
Before leaving the introductory page to minerals in food, it would be good to show what the government recommends as a Dietary Reference Intake (DRI) for some of the minerals listed above.
A DRI isn’t just one number, it is a set of guidelines that includes Recommended Dietary Allowances (RDA), Adequate Intakes (AI) and Estimated Average Requirements (EAR); all segregated by age group, sex and lactation/pregnancy.
For our purposes, we will only give the RDA for some of the macro and trace minerals for male and female adults strictly to bring home how small the actual requirements really are.
Minerals Side Effects
Given the small amounts of dietary minerals we need, it becomes very easy to consume an excess of one or more minerals through supplementation.
An excess of particular minerals can create a host of collateral problems in absorption and bioavailability resulting in deficiencies and other issues that affect our homeostasis (balance in total bodily functions).
Recommended Mineral Allowances for 31 – 50 Year Old Adults
Note that a mg is 1000th of a gram; a ug is one millionth of a gram. There are 28.4 grams in an ounce so with many of these elements we are seeing some very, very small amounts.
In general, it is imperative that we supplement our diets with natural, plant sourced vitamins and minerals…but even this statement is too simplistic.
For example, as was mentioned above, iron from red meat (animal sources) is heme-iron. Iron from vegetable sources is non-heme iron. The source of the iron greatly affects how well it is absorbed in the body.
Animal sourced iron is readily absorbed but not so with plant sources. As a general rule, plant sourced vitamins and minerals in food are superior for absorption but there are exceptions to every rule.