It looks like pond water but a green algae is the superfood which is taking Brighton by storm.

Since being featured in the book of the Channel 4 TV series You Are What You Eat, the food supplement spirulina is flying off the shelves in health food stores.

Shops such as Infinity Foods and Holland and Barrett have reported as much as a 50 per cent increase in sales as people discover the health benefits which presenter and food expert Dr Gillian McKeith raves about.

Mark Shippan, of Infinity Foods, said: "With Dr McKeith's book there been a rise in interest. For people new to this way of eating, the colour could put them off but it's very, very good for you."

Spirulina, which is available as powder, tablets or capsules, starts life as a microscopic algae farmed or naturally found in warm, alkaline, fresh water in countries such as Mexico and Kenya.

Studies have shown spirulina is better digested and absorbed than synthetic supplements and revealed positive results as an immune system simulator and remedy to improve vascular health.

It is one of richest protein sources with more protein than meat - 60 to 70 per cent compared to about 25 per cent - and is a high source of vitamin B12, making it a good supplement for vegetarians and vegans.

Spirulina has a concentration of beta-carotene which is 25 times greater than carrots. This nutrient is turned into vitamin A by the body, necessary for growth, development and night vision.

It is rich in iron and contains essential fatty acids so it may help balance hormones and pre-menstrual tension as well helping tissue repair and the health of the heart, liver and brain. It is believed it helps control blood sugar levels and ease cravings which may make it useful for dieters.

Like leaves, it has the pigment chlorophyll which acts as an antioxidant to help fight the ageing process and detoxify the body, making it beneficial for smokers and drinkers. Antioxidants are also thought to have anti-cancer properties.

Other edible algae varieties with known benefits are chlorella and aphanizomenon flos aquae.

Cathy Robinson, a nutritional therapist who has clinics in Hove and Horam, said: "These days it is getting harder and harder to obtain even the basic essential nutrients from our diet.

"In my clinic I am seeing more and more people suffering from health problems as a result of vitamin and mineral deficiencies.

"In many people digestive difficulties make it harder and harder to obtain nutrients from our food.

"Spirulina is a really great product to use as it is so nutrient-dense as well as being an easily-digested, concentrated source of protein - it really earns its nickname as a 'superfood'. I am convinced that phytonutrients like those contained in spirulina can play a huge part in improving our health."

So how is it best to get a blast of spirulina goodness without being put off by the lurid green colour?

If you are a novice you may opt for the tablet form and knock it back with water but you can also disguise the powder in a smoothie, milkshake, juice or other drink or sprinkled in your food, by adding one teaspoon. If you are not put off by the colour, just add a teaspoon to water. Read the label as the dosage of different brands may vary.

Spirulina is available from health food shops in Brighton including: Infinity Foods, North Road; Sunny Foods, Beaconsfield Road; Health House, Western Road; Holland & Barrett, North Street; and GNC, Churchill Square. Prices start from about £4 and rise depending on quantity and brand.