Best food groups: Fortified cereals, whole grains, nuts, legumes, seeds, tea, leafy green vegetables
Also consider: Okra, oat bran, bulgur, barley, coconut
What is manganese and why is it so important? Manganese is an essential trace element in human body. Many enzymes depend on manganese to create metalloenzymes, which play a role in the utilization of glucose and the breaking down of proteins and fats. It is stored mostly in bones, but you can also see a good amount stored in the kidney and liver. Maintaining a balanced diet high in fruits, vegetables, nuts, and whole grains is the best dietary approach to getting in enough manganese.
Deficiencies include ataxia (lack of coordination), fainting, hearing loss, weak tendons and ligaments, impaired glucose metabolism and reduced insulin production, myasthenia gravis (loss of muscle strength), infertility, diseases of the skeletal structure, impaired growth, elevated blood pressure, atherosclerosis, poor immune function, and selenium deficiency.
How much is enough?
The DV for manganese is 2 mg, based on a 2,000-calorie diet.
When we ingest too much manganese, our body attempts to reduce the amount that is absorbed to protect against toxicity by combining manganese with other minerals, such as calcium and iron. Excess manganese decreases the ability to absorb iron. Iron deficiencies typically only occur if there is long-term exposure to high levels of manganese, but this is rare in a typical American diet and is usually the result of industrial pollution. Symptoms of toxicity are hypertension and Parkinson's-like signs and symptoms.
Did you know? Manganese is a key ingredient in the steel-making process and is responsible for prevention of oxidation or rust. Not surprisingly, manganese functions much the same way in the body, as an antioxidant preventing free radical damage to cells and DNA.
Supplements: Manganese is typically found in multivitamins and bone support formulations. However, it can be purchased as a single ingredient. Supplementing manganese can impact iron absorption. Manganese sulfate is the most common form, found in dietary supplements, but other forms are available.
1. Teff
Teff holds the title of "smallest grain in the world." In fact, it is so small that it was given the Amharic name teffa, which means "lost"—which would most certainly be the case if you were unfortunate to drop a kernel on the ground! When it comes to nutrition, teff is no lightweight, and in fact, besides being the best source of manganese, is an excellent source of copper and a good source of fiber, iron, magnesium, phosphorus, protein, thiamine, vitamin B6, and zinc. Teff has over twice the iron of other grains, and three times the calcium (though it is not considered a "good" source of calcium).
Teff provides the main source of nutrition to over two-thirds of Ethiopians, mainly in the form of a flatbread they enjoy called injera.
2. Pineapple
Canned pineapple (the kind packed in juice) could be yet another shiny example of a shocker food, as it is the second-richest source of manganese and also an excellent source of vitamin C. Pineapple is also rich in an enzyme called bromelain, which has powerful anti-inflammatory properties. An animal study found mice that were fed pineapple juice had markedly reduced inflammation of tissues associated with colitis. However, to obtain this enzyme, fresh pineapple has more bromelain than canned.
3. Pine Nuts
Tree nuts, such as manganese-rich pine nuts, contribute significantly to overall nutrition in those cultures that consume them regularly.
So here's a real shocker, though: It might not be worth your while to depend on pine nuts with any regularity for your daily quota of manganese, or any other nutrient, for that matter. More and more cases of "pine mouth" and allergic reactions have been reported after ingesting pine nuts. Apparently, there is a substance that causes a bitter taste in the mouth after ingesting. Occasional use is probably not a worry, but certainly contact your doctor if you experience swelling or a continued bitter taste in your mouth.
Pine nuts are found within pinecones, but don't eat the kind you may find in your backyard. There are two main species on the market: the Mediterranean or Italian pine nut and the stronger-flavored Chinese variety. The Roman Legions carried pine kernels during their long marches on their quest for dominance.
4. Chickpeas
A study that looked at a variety of legumes found that chickpeas and lentils had the greatest effect on lowering blood glucose after a meal.
5. Hazelnuts
The terms filbert and hazelnut are often used interchangeably as they refer to the same nut. Besides being an excellent source of manganese, hazelnuts are a hotbed of other vitamins and minerals. They are also rich in plant polyphenols, which are mainly found in the outer skin of the nut. Roasting was found to dramatically reduce polyphenols, mainly because the skin was reduced or eliminated in the roasting process.
6. Spinach
Manganese-rich foods like spinach may be helpful in reversing symptoms of deficiencies such as weak muscles.
7. Raspberries
Raspberries are an excellent source of vitamin C and fiber and a good source of vitamin K. Besides being loaded with manganese, raspberries are also high anthocyanins and ellagitannins, antioxidant-rich plant nutrients that may play a role in fighting a host of diseases, including cancer.
Source: USDA National Nutrient Database for Standard Reference, Release 24