Bamfield, British Columbia

 Health and Nutrition

On the Nutritional Value of Kelp

The nutritional constiuents of various types of kelp, while being similar, vary with species, location and time. Generally, kelp are considered to be an excellent source of micronutrients, a good source of some vitamins, and a marginal source of protein. Kelp carbohydrates are indigestible by humans and thus provide hight levels of dietary fibre, but they are not a good energy source.

Comparison of Nutritional Values of Generic Kelp and Cabbage*

Constituent	Percent of dry weight
	Kelp %	Cabbage %
Protein	3.03	1.21
Lipid	0.64	0.18
Cholesterol	0.00	0.00
Digestible carbohydrate	0.00	5.37
Fibre	9.68	0.80
Calcium	0.15	0.47
Iron	0.002	0.006
Magnesium	0.107	0.015
Phosphorus	0.080	0.023
Potassium	0.050	0.246
Zinc	0.0004	0.0002
Manganese	0.0014	0.0002

*Source: Composition of Foods (1984). Agriculture Handbook No. 8-11, US Department of Agriculture, Human Nutrition Information Service.

Comparison of Selected Vitamin Concentrations in Kombu and Spinach*

Vitamin	Kombu	Spinach
B1 (mg/100 grams)	0.08	0.12
B2 (mg/100 grams)	0.32	0.30
Niacin (mg/100 grams)	1.80	0.30
C (mg/100 grams)	11.00	100.00
B6 (mg/100 grams)	0.27	0.18
B12 (microg/100 grams)	0.30	0.00

*Source: Seibin and Teruko Arasaki (1983). Vegetables from the Sea. Tokyo: Japan Publications.

Kelp have the ability to accumulate chemical elements to levels thousands of times greater than their concentration in seawater. Many of these elements are essential for good health and kelp is considered an excellent source of these micronutrients. Kelp also concentrates heavy metals which may be detrimental to good health.

Micronutients such as iron, cobalt, zinc, nickel, iodine, manganese, and magnesium are required for human nutrition in very small concentrations. Mostly these function as co-factors or facilitators to enzymes and vitamins. Without these co-factors the vitamins and enzymes become inefficient or non-functional. For example, iodine is essential to the function of thyroid hormone.

The concentration of micronutrients by the Giant Kelp (Macrocystis)*

Element	Concentration in sea water	Concentration in dry Giant Kelp	Times concentrated over sea water
Iodine	0.06 ppm**	1,016 ppm	16,933
Iron	0.003	127	42,333
Zinc	0.005	23	4,600

*Source: K. G. Rosell and L. M. Srivastava (1984). Canadian Journal of Botany, Volume 62, Pages 2229-2236. **parts per million (1,000 ppm equals 0.1%).