A review of the week’s plant-based nutrition news 30th May 2021
This week I cover the health of modern day vegan children, low carbohydrate diets and type 2 diabetes, the impact of gluten consumption on brain health and an urgent call to action from Greta Thunberg.
HEALTH OF MODERN DAY VEGAN CHILDREN: We don’t have a great deal of comtempory data on the health of vegetarian and vegan children. The cross-sectional VeChi youth study from Germany has provided valuable data in this field. The previous report from this study cohort assessed the energy and macronutrient intake and growth of 430 children aged 1–3 years following either a omnivorous, vegetarian or vegan diet. There were no significant differences in calorie intake, height or weight between the different diet groups. Protein requirements were easily met. Fat and added sugar intakes were higher in children following an omnivorous diet and fibre intake higher in children following a vegan diet. Omnivores were also more likely to be overweight. The report concluded ‘The results of the VeChi Youth Study confirms the position of several national nutrition or paediatric societies that a vegetarian, including a vegan, diet can meet the recommended nutrient requirements in childhood and adolescence’.
This new paper reports the anthropometric measurements, dietary intakes and nutritional status in a cohort of 149 vegetarian, 115 vegan and 137 omnivore children and adolescents between the ages of 6–18 years. The results showed that dietary supplement use was most common in vegan children with most taking vitamin B12 and D3 supplements. Iron supplementation was more common in the vegetarian group. Calorie intake did not differ between diet groups. Protein intake exceded the recommneded 0.9g/kg in all diet groups with carbohydrate intake higher in the vegan and vegetarian groups. Vegans had a lower intake of free sugar and saturated fat, whilst a higher intake of fibre and polyunsaturated fatty acids.
Micronutrients intakes differed between diet groups with vegans having the highest intakes of vitamin E, vitamin B1, folate, vitamin C, magnesium, iron and zinc. Intakes of calcium were lowest in vegans at 305g per 1000kcal, but was below the reference range in all diet groups. Vitamin B2 (riboflavin) intake was also lower in vegans. Of note, vegetarians had a lower than recommended vitamin B12 intake suggesting vegetarians, in addition to vegans, should be encouraged to take vitamin B12 supplements
Regarding blood parameters, vegans had higher folate levels and lower total cholesterol, LDL-cholesterol and ferritin concentrations. Vitamin D3 and B2 were low in a notable proportion of participants regardless of diet groups. This is the first study to assess vitmain B2 levels in children and the clincal relevance of lower than recommended levels in not clear, intakes can be optimised through the consumption of mushrooms, legumes, textured vegetable protein (TVP) or fortified plant-based dairy alternatives.
The main nutrient highlighted that should be optimised in a vegan diet is calcium, especially given recent reports of increased risk of fractures in vegans. Nonetheless, the study concludes once again, ‘The results of the VeChi Youth Study confirms the position of several national nutrition or paediatric societies that a vegetarian, including a vegan, diet can meet the recommended nutrient requirements in childhood and adolescence’.
All in all a very reassuring study supporting a healthy vegan diet as a healthy option for children.
LOW CARBOHYDRATE DIETS FOR TYPE 2 DIABETES: Low carbohydrate diets are popular in the UK for management of type 2 diabetes. This is a welcome report from the Scientific Advisory Committee on Nutrition in the UK. It highlights the difficulty in assessing the current evidence given the lack of definition of a low carbohydrate diet, the differences in nutrients that replace carbohydrates in studies (protein vs fat), the lack of information on the type/quality of carbohydrates consumed and the short follow up of intervention studies. The main aim was to assess the impact of lower carbohydrate diets on body weight, HbA1C, fasting glucose, cholesterol and triglyceride levels in people with type 2 diabetes. Lower carbohydrate diets were in general those in which total energy intake from carbohydrates was less than 47%.
Overall, the recommendations are sensible and appropriately cautious. The report concludes that there are some short term (<6 months) benefits for lower carbohydrate diets on HbA1c, fasting plasma glucose and serum triacylglycerol. There was no consistent evidence of reductions in body weight with lower carbohydrate diets and no differences were observed between higher and lower carbohydrate diets on serum total cholesterol or LDL cholesterol either in the shorter (≥3 to 6 months) or longer (≥12 months) term. The report acknowledges that the data reviewed only relates to Caucasians as there is very infomration on low-carb diets in other ethnicities. In addition, longer term impacts of such an intervention is not known.
The report also makes clear that those choosing a lower carbohydrate diet, should include whole grain or higher fibre foods, a variety of fruits and vegetables and limit intakes of saturated fats as per usual healthy eating guidelines. The advice still remains to consume 30g of fibre a day and therefore this will be impossible unless the majority of the diet is coming from whole plant foods.
The concern for me is the longer term negative impacts of low carbohydrate diets reported in observational studies, which includes increased risk of death from all causes and from cardiovascular disease and cancer. In addition, based on a metablic ward study comparing a plant-based diet to a low carb, animal-based keto diet, the latter actually worsened insulin resistance and resulted in greater loss of muscle mass than body fat. So using a low-carb diet may just to reduce the symptoms of high blood glucose without reversing the root cause of insulin resistance.
The safest and healthiest way of managing type 2 diabetes with the aim of inducing a remission is a whole food plant-based diet as recommended by the American College of Lifestyle Medicine. You can safely lower carbohydrate intake if desired on a plant-based low-carb diet such as the Eco-Atkins diet.
THE IMPACT OF LOW CARB VS HIGH-CARB DIET ON PSYCHOLOGICAL HEALTH: This study from Australia provides a relatively long follow-up of a randomised study comparing different macronutrient combinations for people with type 2 diabetes focusing on changes in mood, quality of life, and cognitive function after 24 months. Both diets were designed to be moderately energy restricted (500–1000 kcal/day) with total energy intake and deficit planned to be energy matched.The low-carb diet was 14% of total energy as carbohydrate (< 50 g/day), 28% as protein and 58% as fat [35% monounsaturated fat (MUFA), 13% polyunsaturated fat (PUFA), < 10% saturated fat, with inclusion of an additional 20 g carbohydrate exchange allowance after week 24 for the remainder of the study. The high-carb diet was 53% of total energy as carbohydrate, 17% as protein, < 30% as total fat (15% MUFA, 9% PUFA and < 10% saturated fat). Core foods provided were: high fibre, low glycaemic index cereal, crispbread, lean chicken/pork/ fish/red meat, almonds and pecan nuts for the low-carb diet. High fibre, low glycaemic index cereal, crispbread, pasta/rice/potato, lean chicken/pork/fish/red meat, legumes for the high-carb diet. All participants also undertook 60 minutes of supervised moderate intensity exercise on 3 days per week.
Of the 115 randomised participants who started the study, 61 completed the 2 years. Both groups benefited from weight loss and reduction in HbA1c with no significant differences between each group. Both diets produced comparable improvements in mood, cognitive function, and diabetes-related quality of life and emotional distress. The degree of weight loss was correlated with the improvements in psychological health. However, this was a supervised programme with professional support and its not clear, given the absence of a control group, whether a self help program would have shown the same improvements.
The main take home message from this study has to be that the best diet is one that a patient is able to sustain and maintain in the longer term. Of note also is that both diets in the study specified <10% saturated fat intake, thus inline with healthy eating guidelines, which advise limiting high fat animal ‘foods’ including red and processed meat. This is certainly a healthier way of adopting a low carb diet.
It’s worth noting that plant-based diets have also been reported to improve psychological health and well-being in people with type 2 diabetes, based on the results of a systematic review. We also know that a plant-based diet is effective at mitigating against some of the common adverse effects of type 2 diabetes, such as coronary heart disease, renal failure and peripheral neuropathy and is extremely effective for weight loss.
GLUTEN AND COGNITIVE FUNCTION: Gluten-free diets have become a popular trend even in people without coeliac disease or gluten intolerance/sensitivity. This has been popularised by books such as Wheat Belly and Grain Brain, but there is little evidence to support the need to avoid gluten for most people. In fact, removing gluten from the diet can often reduce the overall quality of the diet through the avoidance of several high fibre whole grains and there is a suggestion that this may adversely affect health, including increasing the risk of cardiovascular disease. Processed gluten-free products are often lower in protein and fibre and higher in saturated fat and salt than their gluten-containing comparitors.
This study reports finding from the Nurses’ Health Study, specifically examining the impact of gluten consumption on brain health and cognitive function. 13, 494 women with a median age of 60 years were included in the analysis. Long-term gluten consumption was not found to adversely affect cognitive function. In addition, short term changes in gluten consumption did not impact cognitive function. The authors conclude ‘Our findings suggest that restricting dietary gluten for the purpose of maintaining or improving cognition is not warranted in the absence of celiac disease or established gluten sensitivity.’
Whole grains, including those that contain gluten, are an excellent addition to the diet. In a meta-analysis of 45 studies whole grain intake was associated with a reduced risk of coronary heart disease, cardiovascular disease, and total cancer, and mortality from all causes, respiratory diseases, infectious diseases, diabetes, and all non-cardiovascular, non-cancer causes.
THE URGENT NEED TO TRANSITION TO A PLANT-BASED FOOD SYSTEM:
As we pass another World Nutrition day on May 28th 2021, we remember that it has been a year since NHS health professionals wrote to the UK Government and NHS leaders urging policy makers to pass bold post-COVID-19 legislation to allow for rapid and nationwide changes to the unhealthy and unsustainable food environment. Yet there has been very little progress.
Diet-related illness is at epidemic proportion. Recent stats show that 1 in 10 adults over the age of 40 have type 2 diabetes. Almost I in 3 children are now overweight or obese. Our consumption of ultraprocessed foods remains shockingly high and red and processed meat consumption is above recommendations where 0g/d is considered optimal (Eat Lancet). Only 28% of adults and 18% of children consume 5 portions of fruits and vegetables a day.
This unhealthy food environment affects children and families with lower household incomes more. They are being failed by the food system which fails to provide healthy and nutritious food.
A new report called ‘Urban Food Futures’ provides suggested solutions to our unhealthy food environment. It will require 4 main changes.
1. Enshrine access to healthy food as a right for all
2. Enable local communities to have a voice in shaping their future food environment
3. Support value-led businesses that put health and social impact above profit
4. Regulation to ensure that the food system factors in the external costs to health, society and the environment.
Greta Thunberg’s short video is very poignant and clearly lays out the reasons why a plant-based foods system is necessary right now. Let’s continue to demand the changes we need for a healthier future; for people, planet and the animals.
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