Iodine
Some search terms matched…ired thyroid hormone production. Symptoms are not specific.
Food sources
Iodized salt; dairy; seafood; eggs. Seaweed iodine content varies greatly.
Supplement forms
Potassium iodide and sodium iodide.
Before taking a supplement
Excess iodin…
Iron
Some search terms matched… reduced exercise tolerance and, sometimes, cravings for nonfood substances.
Food sources
Meat; seafood; lentils; beans; iron-fortified cereals. Vitamin C helps absorption of plant iron.
Supplement forms
Ferrous sulfate, fumarate and bisgly…
Isoleucine
Some search terms matched…rption and the clinical setting with a qualified clinician.
Food sources
Protein foods such as eggs, fish, poultry, meat, dairy, soy and legumes supply amino acids. The body also makes some amino acids.
Supplement forms
Single-amino-acid pr…
Lavender
Some search terms matched…d. Symptoms are not evidence that you need this supplement.
Food sources
Usually encountered as an herbal preparation or concentrated extract, rather than a source of an essential nutrient.
Supplement forms
Oral, topical and aromatic prepar…
Leucine
Some search terms matched…rption and the clinical setting with a qualified clinician.
Food sources
Protein foods such as eggs, fish, poultry, meat, dairy, soy and legumes supply amino acids. The body also makes some amino acids.
Supplement forms
Single-amino-acid pr…
Lipoic Acid
Some search terms matched…d. Symptoms are not evidence that you need this supplement.
Food sources
Small amounts occur in foods such as organ meats and vegetables; it is also made in the body.
Supplement forms
Alpha-lipoic acid and R-lipoic acid products.
Before tak…
Lithium
Some search terms matched…d. Symptoms are not evidence that you need this supplement.
Food sources
Trace amounts occur in water and food. This does not establish a need for a lithium supplement.
Supplement forms
Prescription lithium salts and over-the-counter lithiu…
Lutein
Some search terms matchedA carotenoid found in foods and in the retina.
Also called: Lutein
What it does
A carotenoid found in foods and in the retina.
What symptoms can—and cannot—tell you
There is no established dietary deficiency syndrome for this specific botan…
Lycopene
Some search terms matched…d. Symptoms are not evidence that you need this supplement.
Food sources
Tomatoes, watermelon and pink grapefruit.
Supplement forms
Tomato extracts and lycopene supplements.
Before taking a supplement
Concentrated supplements can interact w…
L-Lysine
Some search terms matched…rption and the clinical setting with a qualified clinician.
Food sources
Protein foods such as eggs, fish, poultry, meat, dairy, soy and legumes supply amino acids. The body also makes some amino acids.
Supplement forms
Single-amino-acid pr…
Magnesium
Some search terms matched…al heart rhythms. These symptoms have many possible causes.
Food sources
Pumpkin seeds; almonds; spinach; beans; whole grains.
Supplement forms
Citrate, chloride, oxide and glycinate are examples. The label reports elemental magnesium.
Befo…
Maitake
Some search terms matched…d. Symptoms are not evidence that you need this supplement.
Food sources
Cooked maitake mushrooms.
Supplement forms
Culinary mushrooms, powders and concentrated extracts differ.
Before taking a supplement
Concentrated supplements can intera…
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