Today’s Top 5 from TellSpec is shedding light on the topic of metals in your food. What they are, where they come from, and what effects they may have on your health.
First, let’s clear up terms you may have heard:
Heavy metals refers to elements (the things that make up all of life as we know it) that have metallic properties. Heavy metals are not inherently bad; some, like zinc and copper are essential to life; but others, like mercury and lead are considered toxic metals, as significant levels can cause serious illness. However even essential metallic elements can be toxic at a high enough intake.
Alkaline metals refers simply to the group of alkaline earth metals of the periodic table, including calcium. These are distinct from the terms alkali and acidic, which are common in diet discussion.
Alkalinity in that context refers to the pH scale, where something is rated as more acidic or more alkaline (basic); think vinegar and baking soda. So “alkaline foods” or even “alkalized” foods, such as alkalized, Dutch process cocoa, do not necessarily contain significant levels of the alkaline metals.
Elements, minerals, and metals. These terms are overlapping and dependent on context or even quantity. For example copper: copper is a metal in the broad sense, it is also listed as a mineral on nutrition facts labels, and it is an element on the chemist’s periodic table.
The Top 5:
1. Aluminium has no known use within the body, and its main sources within the diet come from trace amounts in food, water, and transfer from aluminium foil and cooking tools. Acidic foods increase the amount of the metal that will leach from contact with aluminium pots, pans, foil, and utensils. Though no conclusive link has been proven, at the intake expected from a typical diet, studies have suggested a link between aluminium and disorders of the brain, including Alzheimer’s, dementia, and hyperactivity. Fortunately aluminium is not very readily absorbed by the body, however older individuals may be more susceptible to aluminium absorption and its effects.
2. Arsenic may or may not be essential to life, though it is certainly toxic at significant levels. Low level and chronic exposure to arsenic can cause nausea, vomiting, and cardiovascular issues, and is associated with increased cancer risk, lung damage, and possible problems in pregnancy and brain development. Sources of arsenic include pesticides, seafood, possibly fruit juices, and rice. Notably, brown rice will typically contain more arsenic relative to its polished white rice counterpart, as arsenic accumulates within the portion of the grain that is removed to form white rice.
3. Cadmium has not been shown to be essential to human health, and its main sources are cigarettes, industrial pollution, and some foodstuffs. Seafood and organ meats have relatively high levels of cadmium, though grains and cereals as well as fruits and vegetables are a source, particularly as they are more common in the diet. Cadmium intake is generally quite low (though low iron increases its uptake), however it does not leave the body quickly and therefore can cause damage later in life. Cadmium is particularly toxic to kidney function, can cause reduced bone density, and is associated with increased cancer risk.
4. Copper is essential to human life, and adequate levels are usually attainable with a healthy diet. Sources include seafood, organ meats, nuts, and legumes. Copper toxicity may be a risk if you make use of unlined, or worn-down, copper cooking implements, particularly if they maintain contact with acidic foods. Exercise caution with copper bowls and pots that have been used for awhile, or come from yard sales. Copper poisoning can cause vomiting, low blood pressure, and gastrointestinal issues; long-term exposure can damage liver and kidneys. High levels of copper within the body is associated with Alzheimer’s disease, though a causal link is not yet confirmed.
5. Lead is a well-known toxic metal, with significant negative health effects with acute and chronic exposure. Long-term effects are particularly concerning as lead takes between months and years to leave the body, during which time it can damage virtually every system in the body, particularly the brain. This is especially concerning for pregnant women, as lead stored in the bones during earlier exposure may be freed during pregnancy and breastfeeding, and can transfer to the baby in-utero or through breast milk, damaging the developing brain. Outside of environmental (air, dirt, dust), occupational, and incidental exposure (lead-containing paints, ceramics, and crystalware), food is a source of lead. Meat and organ meat have the highest levels, but trace amounts can be found in grains, dairy, and even fruits and vegetables. While lead is highly monitored, consumers should make informed decisions when incorporating certain items in their diet.