A recent follow up with a client provided some food for thought (and food for sight) that got me thinking and dusting off a few textbooks. During our session he commented on noticing objects appearing clearer and more colourful since adopting his dietary changes. Was it merely perception, a subjective element spawned by a general improved sense of wellbeing, or is there some possible and real visual mechanism at play? Eating to improve your eyesight?
His nutritional case history:
- An avid cyclist training toward an ultra endurance multi-stage event.
- The desire, and need, to lose weight and specifically fat (non-functional weight).
- A recent increase in weight despite an increase in training load.
- A lack of any nutritional strategy on the bike negatively affecting training and performance.
- No specific medical history or irregular blood tests, recent screening was normal.
- An ex-smoker.
- Irregular symptoms included constant hunger, poor sleep quality/quantity, fluctuating energy levels and inability to maintain concentration.
- No special diet but a diet history showed a high intake of energy, refined carbohydrate, fat and alcohol and a habit of regularly snacking.
What we did:
I am sure some of you have picked up the areas that we worked on. We matched energy intake to his requirements and goals, reduced his intake of refined carbohydrates and moderated fat and alcohol. We increased protein and fiber. We also put together a training and racing strategy. A few changes seemed to nail a number of the issues above most likely through improving blood glucose control** and hunger and satiety cues. Weight loss and body composition improvements were significant, possibly too rapid even, but we mitigated lean mass loss with a higher protein intake.
What could have caused the possible improvements in vision?
It’s not just the carrots…
Looking in greater detail at the foods he limited and the foods he added to his diet provides a number of possibilities that may have helped overcome inadequacies or provided functional foods that may assist vision.
- Vitamin A and zinc deficiencies are not common in western diets or where calories are excessive but worth mentioning as it is possible that subclinical deficiency could still impact vision. Higher rates of zinc loss is also a factor in athletes or those who overdo the booze.
- Vitamin A and zinc rich foods were included in his meal plan which included broccoli, spinach, eggs, cheese, milk, beans, nuts, seeds, oats, cabbage and yoghurt. Alcohol intake was significantly reduced too.
- Lutein and zeaxanthin are two carotenoids that appear to benefit visual function as they both have important roles to play in the retina and are compounds of focus (excuse the pun) for preventing macular degeneration.
- Both carotenoids are found in a number of dietary sources which were common in this clients new diet – spinach, broccoli, lettuce, eggs and avo. Other good sources (although not common in this case) are kale, chard, peas, nasturtiums, zucchini, brussel sprouts and berries.
- At the root cause of many chronic issues is inflammation and visual function does not escape this.
- Although I cannot assume there was an element of inflammation at play it is possible that by improving blood sugar control, limiting refined sugars and removing refined oils there can be an improvement in general inflammatory issues.
- A useful addition to this would be including omega 3 fats in the diet from oily fish along with limiting omega 6 fats from refined plant oils to improve this ratio and help limit a pro-inflammatory immune system.
Weight loss & Sleep
- While not starting this journey obese, body fat levels were above an ideal range and over the first few weeks this client was able to lose over 10% of his body weight and fat weight. This weight loss may have benefited systemic and vascular function and thus improved eyesight over and above the effect specific nutrients may have had.
- Improving quality and quantity of sleep may also have had a positive impact allowing the eyes to rest and recover each day.
My best conclusion is that the improved diet, likely lower blood glucose levels supported by an increase in protein and fiber along with his loss of recently gained weight were players in this game. It is always great to see some beneficial “side-effects” of improving the quality of a diet and whether it was any of these possible mechanisms or the mere placebo associated with the overall improved feeling of wellbeing, well it doesn’t really matter if the outcome is good!
- Kale, chard, spinach and other leafy greens
- Free range eggs
- Salmon, mackerel, sardines, pilchards
- And carrots of course