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I
Inulin
Definition
Fermentable carbohydrate (classified as a fructooligosaccharide or fructan) found in plant foods, such as asparagus, bananas, chicory, dandelion, garlic, Globe artichoke, Jerusalem artichoke, leeks, onions, wheat bran, and wheat flour, that is a prebiotic.1] The average American eats 2.6 g of insulin daily.2 Fermentable carbohydrates may produce gas, bloating, pain, and other undesirable GI symptoms.
Scientific Findings
Inulin improves laxation by increasing stool bulk, water content, and certain fecal bacteria, and may strengthen the intestinal epithelium possibly reducing the risk of gastrointestinal diseases.3,4 Inulin dosed at 15 g daily improved stool frequency in constipated elderly individuals (n = 25) in a 28-day randomized, double-blind, controlled clinical trial (n = 252).5 Gut microbiota improved in inulin-supplemented (0.8 g/dL) formula-fed newborn infants compared to breastfed infants in a double-blind, randomized, placebo-controlled clinical trial lasting for four months.6 See also: Fructan.
Bioactive Dose
For treatment of constipation in the elderly, 20–40 g daily for 19 days has been used.7
Safety
Presumed safe when consumed in normal dietary quantities by nonallergic individuals. People with inflammatory bowel disease (Crohn’s Disease, ulcerative colitis), irritable bowel syndrome, and an estimated 20% of people with celiac disease, could minimize GI distress by avoiding fermentable carbohydrates.8
Iodine
Definition
Trace mineral that functions as part of the thyroid hormones triiodothyronine (T3) and thyroxine (T4) that regulate basal metabolism, growth, and body temperature.9 Chinese medical literature dating to approximately 3600 BC “were the first to record the decreases in goiter size upon ingestion of seaweed and burnt sea sponge.”10 It has been estimated that ⅓ of the world’s population consumes insufficient iodine11 and more than one billion people worldwide are iodine deficient.12 In the US, however, average daily adult intake of iodine has been estimated to be between 210 (140% DV) and 300 µg (200% DV),7 amounts that exceed the Recommended Dietary Allowance and the 150-µg Reference Dietary Intake (used to display % DV). Foods sourced from the ocean, including seafood and seaweed, are good sources of iodine, and sea salt contains some natural iodine; other good sources of iodine are vegetables and fruits grown in coastal, iodine-rich soil. Milk is a source of iodine due to the use of iodophor disinfectants used by the dairy industry (a practice that some commercial dairies have voluntarily discontinued), as well as iodine-containing feed additives given to dairy cows. 13,14 Declaration of iodine content and iodine % DV are not required on Nutrition Facts labels. Additional sources of incidental iodine include iodine-containing dough conditioners used in the bakery industry12,15 and iodine additives used in processed foods such as calcium iodate, potassium iodate, cuprous iodide, and the type of additive used to fortify salt: potassium iodide. The iodization of salt was initiated in 1924 to eradicate goiter in response to high rates of goiter in inland “goiter belt” (Great Lakes, Appalachians, and Northwest) regions of US.8 Iodine is also absorbed transcutaneously from exposure to car exhaust that creates iodine vapor from the combustion of organic fuels and topical exposure to iodine preparations, such as iodine antiseptics.11 Multivitamin-mineral supplements may commonly supply 100% DV for iodine, negating the need for additional iodine intake (Table I.1).
Table I.1 Iodine Content of Common Foods
| 2% milk, 240 ml | 63 μg |
| Nonfat milk, 240 ml | 51 μg |
| Organic 2% milk, 240 ml | Varies by brand, but this information was not available at several manufacturers who were contacted |
| Infant formula, 150 ml | 6.2–56.8 μg |
| Cod, cooked, 3 oz (85 g) | 99 μg |
| Shrimp, cooked 3 oz (85 g) | 35 μg |
| Corn grits, enriched, cooked, ½ cup | 68 μg |
| Bread, 1 (~ 50 g) slice | 23–300 μg |
| Whole wheat bread, 2 slices (50 g) | 32 μg |
| Oatmeal, cooked 1 cup | 16 μg |
| Cornflakes, 3 ½ c (100 g) | 93 μg |
| Flour Tortilla, 1 (55 g) | 41 μg |
| Navy beans, ½ cup (~ 90 g) | 35 μg |
| Baked potato, 1 small (110 g) | 34 μg |
| Turkey breast, cooked, 3 oz (85 g) | 34 μg |
| Salami, (100 g) | 28 μg |
| Cottage cheese, 2% (½ cup) | 26–71 μg |
| Egg, cooked, 1 large (50 g) | 24 μg |
| Iodized salt, 1 teaspoon45 (1 g)46 | 45 μg15 |
| One A Day® Women’s Multivitamin-Mineral | 150 µg47 |
| Centrum Silver Multivitamin-Mineral | 150 µg48 |
Sources: 7, 10, 12–16
Scientific Findings
Both iodine deficiency and iodine excess in otherwise healthy individuals can compromise thyroid function.11 Thyroid enlargement is the earliest clinical feature of iodine deficiency, but excess iodine can also produce goiter.7 Epidemiological studies have shown that an increased incidence of autoimmune thyroid disease frequently parallels an increased dietary iodine intake,16 underscoring the need for adequate, but not excessive, iodine intake. Determination of individual iodine intake is difficult in part because nutrition databases typically do not include iodine. Recent data that are representative of the...
