Five-a-day of fruit and vegetables is good, but 10 is better. A major systemic review and meta-analysis of studies looking at fruit and vegetable intake has found that people who regularly eat 10 portions (800g) of fruit and vegetables a day have a significantly lower risk of chronic diseases. [1] But are all fruits and vegetables good for all of us, all of the time? This article takes a closer look at what to aim for and what to avoid.
Not all fruits and vegetables are created equal
Fruits contain many beneficial minerals, vitamins and antioxidants, but they are also a source of potentially problematic sugars, such as fructose, that can cause health problems if consumed in large quantities. Eating small amounts of whole fruits is fine, however excess fructose consumption has been linked to weight gain and chronic disease. So, whether fruits are good for you, depends on the current state of your health, whether you have a problem absorbing fructose (a problem more common than one realises) and how much fructose you consume via other foods.
"When trying to get your 5 or more portions of fruit and vegetables your mantra should be to eat a lot of vegetables and a few in-season fruits"
Paracelsus (1493-1541), the Swiss-German physician who was considered the founder of toxicology, coined the term “The dose makes the poison.” Fructose at high levels can be toxic. Before 1900, natural fruit consumption accounted for only a small amount of fructose in our diet, in the range of 15g-20g per-day. Today however, the development of high-fructose corn syrup has led to fructose finding its way into many processed foods, such as pizza, soups, breads, biscuits, cakes, ketchup and numerous sauces. Fructose, unlike glucose, does not circulate freely in the blood. The brain, muscles and most other tissues cannot use fructose directly. Instead only the liver metabolises fructose. Excess fructose slowly accumulates in the liver as fat, ultimately leading to fatty liver.
When trying to get your 5 or more portions of fruit and vegetables your mantra should be to eat a lot of vegetables and a few in-season fruits. Aim to eat as many low or medium sugar fruits as possible. These include berries (strawberries, raspberries, blackberries and blueberries), apples, peaches, oranges and avocado (yes, avocado is a fruit).
To juice or not to juice?
Like many things these days, one opinion will tell you how fantastic juicing is and another will warn of the dangers. In a nutshell, the main benefit of juicing is the amount of nutrients (and portions of fruit and veg) you can cram into one glass. Having a nutrient-dense juice or smoothie for breakfast is a great way to start the day.
But tread with caution when juicing fruits, due to the high sugar levels. Vegetable juicing is virtually guaranteed to help you reach your daily target, in an easily digestible form. For best results, the bulk of your juice should come from organic green veg (spinach, celery, kale, Swiss chard, etc.) with a little low/medium sugar fruit added (apple, kiwifruit, a handful of berries or limes and lemons).
Always buy organic?
In a world where chronic illnesses are on the increase and the amount of toxic chemical exposure is becoming more and more accountable, eating pesticide and chemical-free fruit and vegetables is going to help you reduce this toxicity. However organic food is considerably more expensive and therefore not an option for many. The main message here is that the benefits of eating a diet rich in fruits and vegetables has been shown to have positive effects on obesity, digestive health, heart disease, certain types of cancer and more, and that the benefits clearly outweigh the risks. However, for those with specific health issues, who have been told to limit toxin exposure, it is worth being aware of the 2017 edition of The Shopper’s Guide to Pesticides in Produce, released by the Environmental Working Group, which warns that certain fruits and vegetables contain such heavy pesticide loads that it is better to go for organic.
This list of high-toxin foods has become known as 'The Dirty Dozen': cherries, spinach, nectarines, apples, peaches, celery, grapes, pears, tomatoes, sweet bell peppers and potatoes. The same group also identifies 'The Clean 15', the items with the least likelihood of containing pesticide residue and much safer to eat non-organic. These are: sweet corn, avocados, pineapples, cabbage, onions, cauliflower, papayas, frozen sweet peas, asparagus, mangoes, eggplant, honeydew, kiwifruit, cantaloupe and grapefruit. The verdict on washing to remove pesticide residue is not that clear. There are views indicating this can be done using apple cider vinegar, baking soda or hydrogen peroxide (soak 5-10 minutes in bowl of water with the aforementioned added. In the case of berries a quick dunk suffices). There are other views that pesticides are not that easy to wash off as they tend to be absorbed by the plants. However, my advice is to wash – you can reduce the amount of pesticides even if you can’t remove all and in any event from picking, to packaging to your mouth, many hands have touched your fruits and veggies.
Functional medicine appreciates that we are all unique and that the ‘one size fits all approach’ to health issues and treating disease fails in many instances.
Issues to be aware of
Yes. Absolutely. This is where the more personalised approach of Functional Medicine differs to the conventional approach. Functional medicine appreciates that we are all unique and that the ‘one size fits all approach’ to health issues and treating disease fails in many instances. How does this apply to your daily intake of vegetables?
Nightshades: To start with, we have the group of vegetables known as ‘The Deadly Nightshades.’ This food group can aggravate the pain and inflammation of arthritis. It includes white potatoes, tomatoes, eggplant and peppers. These vegetables are not harmful per se, and there is no scientific evidence that they cause inflammation. In fact, they are great sources of antioxidants such as vitamin C and lycopene, which can reduce inflammation and disease. However, nightshades can aggravate inflammation in people who do not tolerate these vegetables well. They can also cause adverse food reactions in individuals with certain autoimmune diseases, particularly those sensitive to lectin, saponin or capsaicin. If you are concerned you may be one of these people, please feel free to contact me for a free 30-minute phone consultation, where we can discuss your individual condition.
Oxalates: Oxalates are not a problem for most people, but in some cases they can act as anti-nutrients, binding with minerals such as calcium, magnesium and iron in your food, and preventing these nutrients from being absorbed. In healthy individuals, moderate quantities of oxalates should not be a problem. However, the following factors can influence the ability of the body to handle oxalates: antibiotic use, overconsumption of foods high in oxalates (spinach, Swiss chard, chia seeds, nuts, rhubarb, plantains, etc.), leaky gut, fat malabsorption, not enough good bacteria in the GI tract to break down oxalates and genetic mutations which impair certain people’s ability to handle oxalates. When oxalates bind with calcium, they form crystals with razor sharp knife-like edges that can be extremely irritating and painful to tissues where they cause an increase in inflammation. People with a predisposition to kidney stones should limit or avoid oxalates. Oxalates can affect every system of the body. Common symptoms include: pain, especially urinary, genital, joints, muscles, eyes, head, intestines; painful or inflamed joints and muscles (like fibromyalgia or arthritis); fatigue; insomnia; burning feet; gas and bloating and more. If you have any of these symptoms check the most comprehensive list detailing the oxalate content of foods in the updated Trying_Low_Oxalates Yahoo group, to ascertain whether your diet may be too high in these foods.
FODMAPs: Iritable Bowel Syndrome (IBS) is on the increase and research today points to Small Intestinal Bacterial Overgrowth (SIBO) as being responsible for as much as 80% of the numerous digestive disorders falling under the umbrella term IBS. [2] In the case of SIBO, there are numerous fruits and vegetables which contain FODMAPS and which are known to exacerbate SIBO. Vegetables to avoid include artichokes, garlic, leek, shallots, onions, sugar snap peas, mushrooms etc. Fruits to avoid include apples, apricots, blackberries, cherries, nectarines, pears, plums, dates etc. If you are struggling with a debilitating digestive disorder and have yet to find the root cause, or feel you could benefit from individual help with a low FODMAP diet, please get in touch.
Cruciferous: If you have a thyroid problem should you be avoiding the cruciferous vegetables such as broccoli, cauliflower, cabbage, kale, Brussel sprouts etc., which contain goitrogens (goiter producers) that can interfere with thyroid hormone synthesis. Fortunately, the goitrogens in these foods are inactivated by cooking, even by light steaming so there is no need to forego the valuable cancer protective, antioxidant effects of these vegetables. Simply avoid eating them raw.
Grapefruit: Beware of dangerous medication interactions. It is a well-known fact that certain chemicals in grapefruit can interfere with the enzymes that break down various medication in your digestive system. As a result, the medication may stay in your system for too short or too long a period. Many people are unaware of this and believe that starting the day with a glass of grapefruit juice is great for their health. Most healthcare practitioners will advise you of the adverse interactions when prescribing medication. However, these interactions occur with over the counter medication as well. If a medication is broken down too quickly, it won’t have time to work and if it stays in the body too long it may build up to potentially dangerous levels. To play it safe, always ask your doctor or pharmacist, when you get a new prescription, about negative reactions to any foods.
Raw, Cooked, or Both?
Here again we read so much conflicting advice. We learn that cooking destroys valuable nutrients and enzymes. Yet we learn that raw can be taxing on the digestive system. And then again, we learn that cooking releases certain important nutrients. What is the verdict? As with most things, it depends. It depends on you and it depends on the foods you are eating. Cooking your food, especially at high temperatures, destroys naturally occurring important enzymes. Increasing the amount of raw food in your diet will help your body produce more enzymes and supply you with vital, live nutrients. However, cooking powers up the nutrients in some vegetables, and does the exact opposite in others. For those with digestive issues eating raw can be a problem and cooking, even if only steaming lightly, makes it easier on the digestive system.
Take a look at my 25 Tips To Get Your Five a Day to learn how to up your daily intake of the nutrient dense, fruit and vegetables, aimed at helping you improve your overall health.
The purpose of this blog has been to highlight that, even with fruits and vegetables, there may still be adverse health consequences for some. So, if you are someone who believes you are doing everything in your power to be healthy and are managing to reach your daily portion target of fruits and vegetables, yet disappointingly still do not feel well, one or more of these highlighted problems may well apply to you.
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