Potassium Summary

Function: Maintains fluid balance, important for nervous system function, maintain blood pressure and a number of cellular functions including muscle contraction
Recommended Daily Intake: at least 3,510 mg of potassium per day (unless specified by your healthcare provider)
Intake too high: If not regulated (in disease) very high levels can cause irregular heartbeat and can be life threatening
Intake too low: Fatigue, muscle spasms, irregular heartbeat, risk of high blood pressure. Severe deficiency can be life threatening
Good sources: Fruits such as bananas, oranges, vegetables such as green leafy vegetables, potatoes and whole grains and nuts.

Potassium is an important nutrient to have in our diet. It plays a large role in muscle function, including the heart muscle, and is key in maintaining normal cell function. Potassium also has health benefits such as helping to lower blood pressure and therefore prevent hypertension, and has been linked with a lower risk of stroke with intakes higher than the recommendations. This is why potassium plays a key role in diet recommendations for individuals at risk of or with cardiovascular disease, but it is also important for the generally healthy population to eat enough of potassium rich foods as well! Many fruits and vegetables like bananas, oranges, apricots, prunes, potatoes, squash, raisins, avocado, and cooked spinach are good sources of potassium. Low fat dairy products like milk, cheese and yogurt, as well as beans and legumes like kidney beans, pinto beans, chickpeas, and lentils are also good sources of potassium. Whole grains also are a rich source.

There are a few situations where you may need to lower your potassium intake, such as with chronic kidney disease or if you are taking certain medications such as a potassium sparing diuretic. Confirm with your health care provider if you need to limit your potassium intake.

Fruits and vegetables that are lower in potassium include apples, strawberries, pineapple, pears, blueberries, asparagus, green beans, cucumber, eggplant, lettuce, peas, and zucchini, and still provide many other health benefits.

Calcium

Function: Important for blood vessels, nervous system, muscle function and bone strength
Recommended Daily Intake: 1,000 mg per day, women over 50 should take 1,200 mg per day
Intake too high: headaches, fatigue, constipation, irregular heartbeat and risk of kidney stones,
Intake too low: Weak bones, muscle cramps, brittle nails, and osteoporosis in women
Good sources: Dairy products such as milk, cheese, dark green leafy vegetables, fortified beverages and cereals, yogurt/kefir, almonds, beans, fish with bones that can be eaten (e.g. salmon, anchovies, sardines, etc.), beans, soybean/tofu, and dried figs

It is important to get enough calcium to help with vascular function, nerve transmission, muscle function and to help prevent bone loss. When we do not get enough calcium from our diet, our body will remove calcium from our bones, making them weaker. Enough calcium in our diet is important all throughout our life, not just when we are older to help prevent osteoporosis! Dairy products such as milk, cheese and yogurt are good sources of calcium, as well as some dark green leafy vegetables (although bigger portion sizes are needed!), tofu, and fatty fish with bones. Some food products have also been fortified with calcium such as fortified milk alternative beverages, fortified juice and some breakfast cereals. In some cases, if you are not able to get enough calcium from your diet, a supplement may be recommended – talk to your health care provider.

Magnesium

Function: Important for making proteins in the body, DNA replication, nervous system function, blood sugar control, and blood pressure regulation
Recommended Daily Intake: 400-420mg for men, 310-320 mg for women
Intake too high: diarrhea, vomiting, muscle weakness, low blood pressure
Intake too low: nausea or vomiting, fatigue, muscle weakness
Good sources: nuts, grains, green leafy vegetables like spinach

Magnesium is an important mineral for protein creation, muscle and nerve function, blood glucose control, and blood pressure regulation. This is why is it important to individuals with hypertension to meet magnesium recommendations. Magnesium can be found in many fibre containing foods like whole grains (whole grain bread, brown rice), nuts and seeds (pumpkin seeds, almonds, cashews), green leafy vegetables like spinach, as well as any type of beans and legumes, like black beans, edamame.

Sodium

Function: Maintains muscle functioning, fluid balance and blood pressure
Recommended Daily Intake: less than 2100 mg per day
Intake too high: Fluid retention and hypertension
Intake too low: Nausea, vomiting, headaches, muscle cramps
Foods to Minimize: Processed meat, canned foods, packaged foods and seasoning mixes

Sodium is a mineral that is needed by our body in certain amounts for proper muscle functioning, fluid balance and blood pressure. However, too much sodium can have negative effects such as fluid retention and high blood pressure, which is a risk factor for developing heart disease and increased stroke incidence. There is also a relationship between the amount of sodium consumed and the risk of developing these adverse health effects; this means that the more sodium you eat, the greater your risk of developing heart disease. This is why it is very important to follow a low sodium diet if you are at risk of or have heart disease, or kidney disease.

As a society, we often consume too much sodium because it is abundant in many foods, especially processed foods since it is used to flavour and help preserve food products. Foods that tend to be high in sodium include canned foods like canned soups, stews and chilis and canned baked beans, processed meats like deli meats, hot dogs and sausages, condiments like ketchup, relish and toppings like pickles, sauerkraut and olives, packaged convenience foods such as frozen dinners, packaged side dishes with seasonings such as rice or pasta dishes, and seasoning mixes. More salt/sodium comes from these types of packaged foods compared to the amount of salt we add at the table or during cooking, although we do need to watch how much we add to our food.

To lower the amount of sodium in your diet, you can season your food with salt free seasonings or herbs and spices, look for canned foods with ‘no salt added’ or ‘low sodium’ labels, and check the nutrition facts table for products that have less than 15% daily value (DV) of sodium per serving. You can also use smaller portion sizes of condiments and sauces. Eating more whole foods like fruits and vegetables and whole grains can help naturally lower your sodium intake, and increase your potassium intake, which has been found to help reduce blood pressure when consumed in adequate amounts (meeting or exceeding potassium recommendations).

There are some cases where your health care provider may actually recommend that you increase your salt intake, but the majority of individuals should aim to consume less than the recommendations.

Iron

Function: Important for growth, neurological development and red blood cell function.
Recommended Daily Intake: Men 8 mg per day and Women 18 mg per day
Intake too high: Not a concern if comes from diet. Very high levels are toxic and can damage multiple organs.
Intake too low: Maybe slow to gain weight, likely to be tired, lack appetite and be anemic.
Good sources: High heme iron foods (these have better absorption): chicken liver, mussels, oysters, beef, sardines.

Non-heme sources: fortified cereals and oatmeal, beans, seeds, chickpeas, tofu, wheatgerm, pumpkin seeds, green leafy vegetables

Iron is a mineral found in some foods that we eat that helps your red blood cells carry oxygen throughout your body. It is also needed for growth and neurological development. Many individuals do not meet their iron requirements, so it is an important nutrient to discuss. Eating enough iron helps prevent anemia, which can lead to fatigue, shortness of breath or chest pain. Iron can be found in both animal products and plant products, however it is often better absorbed by animal sources of iron such as meat and seafood. Choosing lean meats (chicken and turkey) and seafood over red meats (beef, veal, pork, goat and lamb) is recommended to lower saturated fat intakes. Plant sources include green leafy vegetables like spinach, but also beans and legumes (white beans, kidney beans, chickpeas, and lentils) and tofu, however they need to be consumed in larger portions that meat sources of iron. Some foods are also fortified with iron such as fortified breakfast cereals (look for ones with more than 4g of fibre and less than 10g of sugar per serving) and whole grain and enriched bread products. Combining these foods with foods that contain vitamin C can help absorption of iron. Examples of food high in vitamin C are oranges, or other citrus fruits, bell peppers, strawberries, brussel sprouts, broccoli, and melons.

Other Resources

Phosphorus

Learn more from Harvard School of Public Health here