Iodine is an important mineral that plays vital roles in the body necessary for growth and development.
Iodine is required to produce hormones by the thyroid gland.
These thyroid hormones, in turn, play other functions like regulating bone and brain development in infants.
Low levels of iodine than normal in the body caused hypothyroidism which is the inability of the thyroid gland to produce enough hormones.
Deficiency of iodine is more common in women than men, and hence it is very important to ensure appropriate iodine levels in the pregnant and lactating women as it can have an effect on the development of the infant.
The widely observed symptom of iodine deficiency is an enlarged thyroid gland.
People suffering from iodine deficiencies are recommended iodine supplements with appropriate dosage. The dosage depends on the age of the individual. 
Which are the Conventional Iodine Supplements?
There are various natural food sources that are rich in iodine like fish, dairy products like milk, yogurt and cheese, fruits and vegetables and iodized salt.
However to ensure that the person is consuming enough amounts of iodine to prevent medical conditions doctors recommend supplements with appropriate dosage.
Iodine is present in most multivitamin supplements. Dietary supplements are also available that contain high amounts of iodine in the form of potassium iodide or sodium iodide
What are the Side Effects?
Iodine supplements can cause significant side effects on the excessive intake or if the appropriate dosage is not followed.
Side effects of consuming a large dose of iodine include nausea, vomiting, diarrhea, coma, inflammation of the thyroid gland, thyroid cancer.
It can increase the risk of an overactive thyroid gland causing hyperthyroidism. Iodine supplements may interact with other drugs taken by the patient and cause adverse effects on the body.
They may interact with anti-thyroid drugs used to treat hypothyroidism. 
Since iodine present in supplements is in the form of potassium iodide, its excessive intake may increase levels of potassium in the body and can be fatal.
It is recommended to consume more natural sources like fruits and vegetables rich in iodine instead of opting for dietary supplements that have a risk of causing potential side effects.
What is Kelp and its Nutritional Profile?
Kelp is a large seaweeds belonging to the family of brown algae. They absorb high amounts of iodine from seawater serving as good natural sources of iodine.
Kelp is also rich in nutrients like essential vitamins and minerals, enzymes, proteins, and polysaccharides. The nutritional profile of 100 grams of Kelp is as follows:
Energy- 180 KJ
- B complex vitamins - 0.91mg
- Vitamin C- 3mg
- Vitamin E – 0.87
- Vitamin K- 66µg
- Calcium- 168mg
- Magnesium- 121mg
- Potassium- 89mg
- Sodium- 233 mg
- Carbohydrates – 9.57g
- Proteins – 1.68g
- Fats - 0.56g
What is the Iodine Content of Kelp?
Different species of kelp differ in their iodine content. Following table shows the iodine content of different species of kelp when consumed in a particular form.
Why is Kelp Better than Iodine Supplements?
Kelp is a natural source of iodine enriched with various other nutrients.
It has mild side effects and the ability to treat hypothyroidism if consumed on a daily basis in appropriate amounts.
Iodine supplements, on the other hand, are most often devoid of nutrients and contain iodine which on excessive intake produces side effects.
Iodine supplements contain iodine in the form of potassium or sodium iodide that can increase levels of potassium and sodium that were unnecessary and create further complications.
Kelp is a balanced nutritional supplement containing a variety of minerals in small amounts.
Pure iodine supplements can be used for preventing harmful effects of radiation on exposure, healing wounds, mouthwash to treat oral inflammation and other uses.
Those who wish to opt for a natural source of iodine can begin use of kelp on a daily basis to observe effective positive results.
Dosage of Kelp
There is no specific dose of kelp for health.
Kelp has received GRAS status. Mean intake of kelp in Japan is 7g per person per day. 
According to the FDA the intake of kelp should be limited to a dose of 0.15- 0.25 mg of iodine. 
This should be around 1g of kelp but the iodine contents vary with every species.
It is best to consult a health practitioner before consuming kelp in any form if you have thyroid issues.
The book, Drug Abuse Treatment Using Biochemistry mentioned that Kelp is seaweed that can be consumed raw but is usually processed in the powdered and dried form so that it can be used as a flavoring agent in dishes and can be easily included in the diet.
It is rich in nutrients and is mostly available as a supplement in the market. 
Iodine supplements, as well as kelp, may have potential side effects it not taken in the dosage prescribed for a particular condition.
As mentioned before high doses of iodine in the body can often result in a reduction in the production of thyroid hormones leading to hypothyroidism in a person with normal thyroid function.
Thus, iodine supplements have side effects and interactions with other medication. These must be consumed in appropriates doses after consultation from a medical practitioner.
Those opting for natural sources of iodine can consume kelp containing food products, as a sea vegetable in salads or powdered form in beverages or supplements in the form of capsules or tablets.
This will provide you with nutrition along with treating iodine deficiencies.
There is evidence that foods containing algal species often contain high amounts of metal ions and excessive uptake of such foods can lead to metal toxicity.
High arsenic content present in seafood including kelp can lead to harmful effects like an accumulation of metals or toxicity in the body and cause mutations like cancer.
Mild allergic reactions like inflammation may occur on the consumption of kelp since it is a marine alga.
One must avoid its consumption if any such side effects are observed. It is best to start the intake in small amounts and then increase the dose gradually.
Be careful to buy kelp containing food products and supplements from safe and trusted places to ensure its safety and follow the recommended dose.
Excessive intake can cause problems like metal toxicity or even cancer.
Pregnant and lactating women should avoid consumption of kelp as a vegetable or in the form of supplements.
Those on medications must avoid kelp supplements and if taking them must maintain a gap of 3-4 hours between the two to avoid interactions between the two.
Those who have cancer or other diseases and on medications must consult a doctor before its consumption.
Considering all facts regarding the two iodine sources, consumption of dietary kelp can be considered safer and more effective than consuming pure iodine supplements in that it not only provides iodine but is also rich in other essential nutrients that will help in healthy growth and development of an individual.
However, one should not exceed the recommended dietary intake of iodine.