The Urban Kitchen – Pros and Cons of Restricted Diets

Every year, there are new diet trends, some disguised as ways to improve your health, but in reality, these trends are often another way to restrict nutrient and calorie intake. Popular diets have often insisted on cutting out major food groups including gluten or carbohydrates, dairy and sugar, often going meat free, high fat or plant based. But are all of these diets actually healthy and providing us with the nutrients that we require?

Part of the problem is that there are so many variables determine our eating patterns and requirements – how much we have slept, our genetics, how much we exercise, stress, lifestyle and environment that it’s difficult for researchers to conclude on what is the best diet and how to best prevent various diseases. We all know that eating more vegetables and fruits is beneficial but after this, it’s hard to separate out the data from the dross, particularly with popular media twisting scientific research results to make it more newsworthy.

Going gluten free seems to be de rigeur if you are in the wellness world – it’s often treated as Kyrptonite is to Superman! But gluten is merely a protein found in grains such wheat, rye and barley. Those who are coeliac have an immune reaction to gluten, which causes impaired absorption and digestion of nutrients in the intestine. For these people, it’s incredibly important to avoid gluten so that they are able to digest and absorb other nutrients. But for those who are not coeliac, avoiding gluten could increase the risk of heart disease as it deprives people of the many benefits of whole grains.

A recent paper published in the BMJ , examined food questionnaires from almost 65000 women in the Nurses Health Study and over 45000 men in the Health Professionals study over 26 years to find that avoidance of gluten potentially reduced the consumption of beneficial whole grains which are important for reducing cardiovascular risk. Dietary fibre from whole grains, as part of a healthy diet, can support in reducing LDL levels (bad cholesterol) and potentially reduce the risk of heart disease, stroke, type 2 diabetes and obesity.

Dietary fibre, particularly insoluble fibre in wholegrain breads and cereals, is also important for gut health as the beneficial bacteria ferment and digest this and keep our digestive system regular. The beneficial bacteria metabolise insoluble fibre to produce short chain fatty acids, which are important signaling molecules which ensures that the gut lumen (inside of the gut tube) has limited oxygen, which prevents the growth of pathogenic bacteria such as Salmonella or E.Coli from growing .

Dairy is another food group which people love to avoid for a wide range of reasons such as weight loss, preventing inflammation and disease, clearer skin and better digestion. Dairy, particularly milk, consumption has steadily declined in the last decade in the UK. But what is the impact of this on our health?

Our bones are constantly being remodelled with osteoclasts reabsorping the bone, releasing minerals such as calcium into our blood. Osteoblasts deposit bone in a process called ossification. After the age of 30, our bone reabsorption is much higher than bone is deposited. The best way to stop our skeleton and bones from disintegrating is by consuming sufficient levels of calcium and vitamin D. The body absorbs calcium better than from dairy than any other food, according to Rebecca Blake, RD and director of clinical nutrition at Mount Sinai Beth Israel Health.

Our recommended daily requirement of calcium is 1000mg so a glass (200ml) of cow’s milk or kefir provides us with 240mg of calcium, almost a quarter of our daily requirement. 200g of yoghurt provides 260mg and 30g of hard cheese provides 240mg of calcium. But there are other plant based foods which are high in calcium but you need to carefully balance these as some are more bioavailable than others. 2 cups of kale contains 200mg of calcium but although other greens such as spinach and chard contain lots of calcium, this is not bioavailable as they also contain oxalic acid. Bok choy, almonds, chia and sesame seeds all have bioavailable calcium so perfect for a vegan or plant based diet. Calcium set tofu is also high in calcium but sadly not all tofu is made in this way.

One of the other pitfalls of removing dairy from your diet is that you also remove probiotics present in yoghurt and soft cheese. Fermented dairy foods are a popular way to ensure that we are getting plenty of beneficial bacteria into our digestive systems, ensuring that we are regular and have soft stools . Fear not, you can take probiotics or eat other fermented foods such as sauerkraut, tempeh and kombucha.

So my advice is avoid all the fad diets and cutting foods out (unless you are allergic!) and add in as many different foods as possible to improve your gut health and ensure that you are getting the widest range of micronutrients.

i Long term gluten consumption in adults without celiac disease and risk of coronary heart disease: prospective cohort study
BMJ 2017; 357 – Lebwohl et al

ii Microbiota-activated PPAR-γ signaling inhibits dysbiotic Enterobacteriaceae expansion
Science  11 Aug 2017:Vol. 357, Issue 6351,- Byndloss et al

iii The effect of probiotics on functional constipation in adults: a systematic review and meta-analysis of randomized controlled trials
The American Journal of Clinical Nutrition, Volume 100, Issue 4, 1 October 2014, Pages 1075–1084-  Dimidi et al

“- Toral Shah, The Urban Kitchen

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