Question

The iodide ion is a dietary mineral essential to good nutrition. In coun tries where potassium iodide is added to salt, iodine deficiency (goiter) has been almost completely eliminated. The recommended daily allow ance (RDA) for iodine is 150\(\mu g /\) day. How much potassium iodide \((76.45 \%\) I) must you consume to meet the RDA?

Short answer

To meet the RDA for iodine, one must consume approximately 196.21 \(\mu g\) of potassium iodide.

Step-by-step solution

Analyze the Composition of Potassium Iodide

Determine the percentage of iodine in potassium iodide. Given that potassium iodide is 76.45% iodine, this means that for every 100 mg of potassium iodide, there are 76.45 mg of iodine.

Calculate the Required Amount of Potassium Iodide

To find the required amount of potassium iodide to meet the RDA for iodine, use the percentage of iodine in potassium iodide. You set up a proportion where 76.45% (or 0.7645 as a decimal) corresponds to the 150 \(\mu g\) RDA: \[0.7645 \text{ mg I} / 100 \text{ mg KI} = 150 \mu g \text{ I} / x \mu g \text{ KI}\]. Solve for \(x\), the amount of potassium iodide needed.

Solve the Proportion for Potassium Iodide

Cross-multiply and divide to find the amount of potassium iodide needed to get 150 \(\mu g\) of iodine: \[ x = \frac{100 \mu g \text{ KI} \times 150 \mu g \text{ I}}{0.7645 \mu g \text{ I}}\].

Calculate the Precise Dosage

Perform the calculation to determine the exact amount of potassium iodide needed: \[ x = \frac{15000 \mu g \text{ KI}}{0.7645} \approx 196.21 \mu g \text{ KI}\]. So, you must consume approximately 196.21 \(\mu g\) of potassium iodide to meet the RDA for iodine.

Key concepts

Potassium Iodide

Potassium iodide is a compound that plays a crucial role in maintaining thyroid health by providing the body with iodine, an element necessary for the production of thyroid hormones. These hormones are vital for regulating metabolism, growth, and development.

Chemically, potassium iodide is represented by the formula KI and contains about 76.45% of elemental iodine by weight. This means that in every 100 milligram (mg) sample of potassium iodide, there are 76.45 mg of pure iodine. When iodine is paired with potassium, it becomes more stable and easier for the body to absorb, making potassium iodide an efficient way to deliver iodine nutritionally.

Choosing potassium iodide as a dietary source is particularly beneficial because it is easily incorporated into a variety of products, such as iodized salt, which is common in many household kitchens. Ingesting potassium iodide through iodized salt has been a successful public health strategy to prevent iodine deficiency across populations.

Iodine Deficiency

Iodine deficiency can have serious health implications because iodine is essential for thyroid hormone production. Without adequate iodine, the thyroid gland struggles to make these hormones, which can lead to a variety of disorders.

One of the most common outcomes of iodine deficiency is goiter – an enlargement of the thyroid gland. Goiter, which presents as a noticeable swelling in the neck, occurs as the gland tries to compensate for the lack of iodine. In children, inadequate thyroid hormones due to iodine insufficiency can cause cretinism, resulting in stunted physical and mental growth.

Because iodine deficiency is preventable, many countries have implemented programs to add iodine to table salt. This relatively simple intervention has markedly reduced the occurrence of iodine deficiency and its associated risks. Understanding the role of iodine and how to prevent its deficiency is of public health importance.

Recommended Daily Allowance

The Recommended Daily Allowance (RDA) for iodine is the amount considered sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in a specific life stage and gender group. According to health organizations, the RDA for iodine is set at 150 micrograms (\( \text{µg} \) per day for the average adult.

This guideline helps in preventing both deficiency and excess, as too much iodine can also lead to adverse health effects like hyperthyroidism or thyroiditis. RDA values are used by professionals to advise individuals on their daily nutrient intake and to plan and assess dietary programs for populations. Notably, the iodine RDA varies by age, sex, and life stage, with different values set for pregnant and lactating women due to the increased demand for thyroid hormones during these times.

Chemical Composition Analysis

Chemical composition analysis involves determining the percentage of different elements contained within a compound. Knowing the exact composition of a substance like potassium iodide is critical for applications in nutrition, where precise dosages are required. For example, if we know that potassium iodide consists of 76.45% iodine, we can calculate the amount needed to fulfill the RDA for iodine.

To determine how much potassium iodide one needs to ingest to meet their dietary iodine requirements, a simple mathematical calculation can be performed. This involves setting up a proportion based on the iodine content percentage in potassium iodide and solving for the unknown amount of the compound required to achieve the desired amount of iodine. This quantitative insight is vital in nutritional science and food chemistry, ensuring that individuals receive the correct amount of essential nutrients like iodine from their diet.