Common Nutrient Deficiencies and Guidelines for Healthy Eating
by Dr. Louise Gagné

WHAT IS SO BAD ABOUT THE STANDARD NORTH AMERICAN DIET?

It’s really about how much processed foods people eat. Processed foods, for the most part, are depleted of nutrients. We can fill up on them, but we aren’t necessarily going to meet our nutritional needs. Therefore, people can end up with multiple nutritional deficiencies, if they eat a diet that is heavy on processed foods.

Surveys in Canada have shown over 40% of total calories consumed by Canadians come from ultra-processed foods (soft drinks, instant noodles, packaged cookies and snacks, fast food, frozen meals). Children over the age of 5 and adolescents were found to be the highest consumers of these foods.

COMMON NUTRIENT DEFICIENCIES

Common nutrient deficiencies and insufficiencies in North America include:

• Minerals: calcium, magnesium, potassium, iron, zinc, copper
• Fat-soluble vitamins: vitamin A, vitamin D, vitamin E, vitamin K
• Other Nutrients: omega-3 fatty acid, fibre, vitamin C, vitamin B6

These nutritional deficits have measurable negative effects on population health.

Let’s take magnesium and potassium, as examples, and look at why many people are deficient in them.

If you don’t get adequate magnesium in your diet, you are much more likely to be susceptible to developing Type 2 diabetes. Magnesium deficiency is also linked to an increased risk of heart arrhythmia (an irregular heartbeat). Good food sources of magnesium include whole grains, nuts, legumes, and green vegetables. However, many people rarely consume these foods and thus are unlikely to get enough magnesium. For instance, if you eat white rice instead of brown rice you get 78% less magnesium. Eighty-five percent of magnesium has been removed from refined grains and soy protein isolate.

Low potassium intake is linked to an increased risk of pretty well every chronic illness out there. Good food sources of potassium include dried apricots, avocadoes, roasted soy nuts, and baked potatoes. Moreover, there is potassium in virtually all unprocessed plant foods. The biggest reasons for low potassium intake are low consumption of fruits, vegetables, and legumes in the general population, and significant losses of potassium due to cooking methods. For example, you can lose 70% of the potassium in your vegetables if you boil them in water, and then pour that water down the sink.

WHAT ELSE IS WRONG WITH THE STANDARD NORTH AMERICAN DIET?

There tends to be an excess of saturated fats, omega-6 fatty acids, sodium, phosphorous, high glycemic index carbohydrates, along with added sugars and high fructose corn syrup.

WHAT TO DO?

It’s not practical to get up each morning and think about how to obtain all the fatty acids, amino acids, vitamins, minerals, phytonutrients, fibre, etc., that are essential for optimum health. Thus, we need some general rules of thumb. First, I recommend eating whole foods, in other words foods that have been minimally processed with very few nutrients removed and no potentially harmful substances (such as artificial colouring agents) added. Let’s say 80% of your diet is whole foods. Right there you are going to increase your intake of all the wonderful micronutrients. Second, work on enlarging your repertoire of the different kinds of things you eat, making it more likely you will get all the little micronutrients that you need.

WHAT TO LOOK FOR IN A HEALTHY MEAL/HEALTHY DIET

• Flavourful, appealing, colourful
• At least 2 servings of fruits/vegetables per meal
• Adequate but not excessive calories
• Nutrient density
• Phytochemicals and fibre
• Low in sodium and added sugars
• Eating a wide range of colours and kinds of fruits and vegetables will provide a variety of nutrients and phytonutrients

WHAT TO AVOID, OR REDUCE, IN A HEALTHY MEAL

• Highly processed, nutrient-depleted foods
• High glycemic index carbohydrates
• Excessive sodium
• Foods containing toxic compounds such as heterocyclic amines, mercury, and dioxins

NUTRIENTS YOU MAY NEED TO SUPPLEMENT

As a general rule, if you eat a wide variety of whole unprocessed foods, you should be OK in terms of things like zinc, potassium, magnesium, iron, copper, most of the B vitamins, vitamin K, vitamin E, etc. If you approach food in that way, it should look after most nutrients.

However, certain nutrients are an exception to this rule, namely any nutrient that is only present in substantial amounts in a relatively small number of foods. Depending on your diet, the key ones you may need to supplement are iodine, calcium, vitamin D, and omega-3 fatty acids. Vitamin D is especially hard to get during the winter months in Saskatchewan. In the case of omega-3 fatty acids, over 90% of North American diets do not contain an adequate amount.

Thus, I recommend taking a good quality, balanced multivitamin/ multimineral. If your diet is low in omega-3 fatty acids, also consider taking a good quality, high potency fish oil supplement with at least 600mg EPA + DHA per capsule.

If a vegan diet is being followed, you must plan very carefully to get enough calcium, iron, vitamin B12, and flax instead of fish oil. Vegans should have vitamin B12 levels checked on an annual basis.

COOKING METHODS MATTER

Fifty to eighty percent of certain nutrients may be lost during cooking. For example, more than 50% of vitamin C is lost if mixed vegetables are boiled for 10 to 20 minutes. Only 25% of vitamin C is lost if mixed vegetables are steamed for 3 to 5 minutes.

As a general rule, the less time your food is exposed to heat, oxygen, or light, or submerged in water, the less nutrient losses. To reduce nutrient loss, try to cook your vegetables in just small amounts of water, so that when they are done, there is very little, or no water, left.

Try to make use of your vegetable steaming water in soups and stews to retain nutrients that would otherwise go down the drain, such as folate, vitamin C, magnesium, vitamin B6, and potassium.

Also, to preserve nutrients, leave the skin on foods like carrots and potatoes and chop vegetables in larger pieces. The more you chop things up and peel them, the more nutrients you’re going to be losing into the water and in the peels.

The material in this article was prepared by Dr. Louise Gagné. Louise practiced medicine in Saskatoon for over 35 years and completed a Fellowship in Integrative Medicine at the University of Arizona with Dr. Andrew Weil. She taught nutrition and integrative medicine at the University of Saskatchewan for 15 years. This article was sourced from both her spoken and written words in a presentation she made at the University of Saskatchewan. Dr. Gagné passed away in 2023, but her exceptional knowledge continues to be shared.