Tag Archives: Colour

Do you see in black and white?

“What does Red look like to you?”, and “Are you like a dog then?” are some of the many questions people suffering from colour blindness get once their genetic deficiency is uncovered. Not only are these questions woefully ignorant, but they are grossly exaggerated from the implications of the term “blindness”. This occurs since people normally attribute blindness as a condition in which an individual cannot see whatsoever, however in reality even individuals who are considered “blind” have some visual perception. In accord with this, colour-blind people are not absolutely blind to colour, with many simply having difficulty differentiating between shades of colours such as green or red. This is why colour-blindness is identified in the spectrum of Colour Vision Deficiency, or CVD for short.

Most people understand that we see things because of our eyes, but don’t actually understand how this happens, and as a result they also have difficulty understanding how CVD occurs, so a short description is provided here. In the eye, the retina is the component which receives incoming light and transmits the corresponding information to the brain resulting in colour perception. This is done by the approximately 6 million cone cells, which are categorized into the red, green, and blue types, and all individually respond to different wavelengths of light. Colour vision deficiency occurs when an individual’s eyes are unable to sense certain wavelengths of light under normal conditions due to some issue with their cone cells.

With this description, it is still difficult to visualize what it really means to be colour vision deficient, since you can’t simply switch off your cones to experience this, whereas you could close your eyes to simulate blindness. To put it simply, people with CVD, such as myself can’t see quite as wide a range of colours that a person with normal colour vision can (a great description of this can be found at this website). The outcome of this is mainly confusion for the CVD individual, with common interactions such as “Do my shoes and dress match?”, “Can you pass me the red backpack?”, or “The red line shows X, while the green line shows Y” leading to misunderstanding. Granted that such interactions can be quite humorous, the individual is often left feeling oblivious and naïve. So next time you meet someone who is colour-blind, just saying “Your eyes are pretty” will probably make their day.

Dangers of Artificial Food Colouring

Artificial food dyes are additives that are used to enhance the colour of various foods. The food industry has used food colouring as a tactic for many centuries to make food look more appealing to consumers. Would you rather eat a colourless lollipop, or a rainbow coloured lollipop? Although artificial colouring is widely used, it is linked to a number of health problems such as cancer in animals and increased hyperactivity in children.

Lollipop (By Graham and Sheila)

For many of us, it is almost impossible to go a day without consumption of artificial colouring. Colouring agents are found in beverages, candies, cereals, and in most processed foods. Health Canada has permitted 13 colouring agents that are considered safe, including Brilliant Blue (or Blue #1), Allura Red (or Red #40) and Tartrazine (or Yellow #5), the 3 most common colouring agents.

In “Food Dyes: a Rainbow of Risks”, CSPI (Center for Science in the Public Interest) revealed health issues linked to nine food dyes. For instance, Citrus Red 2, which is used for colouring the skins of oranges, is toxic to rodents and is linked to bladder tumor. Yellow 5, which is used in beverages, cereals, and yogurts, may be contaminated with cancer-causing chemicals and is linked to hypersensitivity reactions in children.

A study published in 2007 also found that artificial colours increased hyperactivity in children. The results were achieved from 267 studies in 3 year old and 8/9 year old children. The children were given a placebo drink, or a drink containing artificial colouring equivalent to the amount of colouring found in two bags of sweets. The children consumed the drink everyday for a total of 6 weeks. During the study period, three measures of behaviour, the ADHD rating scale, the hyperactivity scale and the classroom observation code were used to study the hyperactivity in children. The researchers found that the results were consistent with those from other studies.

Top: Chocolates coloured with Brilliant Blue. Bottom: Chocolates coloured with natural spirulina (By John Penton)

Although there are potential health effects linked to artificial food colouring, I still want my M&M’s chocolate and Jell-O to be coloured. Thankfully, more companies are looking for natural alternatives to replace artificial colours and meet the public’s desire for natural products. Natural colour sources such as cyanobacteria Spirulina can replace Brilliant Blue, curcumin from turmeric can replace yellow, and chlorophyllin from chlorella can replace green. Furthermore, Health Canada has set many restrictions to limit the amount of food colours that can be used, and the types of food the colours can be added to. However, if you are concerned and want to limit artificial colours in your diet, look for food labels that say, “no artificial colours”, or shop at grocery chains that do not sell food with artificial colouring, like Whole Foods Market.

An interesting video that talks more about the potential health effects of artificial food colours is shared below.

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Carmen Chu