Sources

We believe that signposting sources behind science claims and learning to understand them is essential:

• To improve our understanding of how our body works and uses food components

• To help us move away from the 'magical pill' mindset, uncovering the grey areas of nutritional science where a lot is still misunderstood and unknown

• To be transparent about what resources we have used for health goal criteria

• To better understand what the science shows and educate our users

‘Backed-up by science’ or ‘evidence-based’ are often used as words to prove accuracy and reliability. However, with science also comes bias, overgeneralisation, negligence and inaccuracy.

Aligned with our core value of transparency, we decided to include all sources, including those with mixed or negative results. These are important to highlight the complexity of nutritional research and to learn to be comfortable in the 'grey area', where no ingredient is seen as a panacea to fix health issues.

Our research team searched through scientific databases, such as PubMed and Cochrane, to identify high quality studies looking at the effects of dietary patterns, whole foods or nutrients on our health goals. We screened each identified article for eligibility, based on pre-established criteria, such as the type of study and the population studied. We analysed selected research papers and extracted the results to create a detailed spreadsheet for every health goal.

1. We compiled nutrients and whole food recommendations extracted from the research into a spreadsheet for every health goal
2. To ensure each recipe met the recommendations, we generated a simple algorithm to 'validate or reject' against our criteria.
3. For each recipe, we entered the ingredient amounts into the appropriate spreadsheet to check whether they met the criteria for our health goal

Research guides us toward dietary components to include and patterns to be aware of. However, the many flaws of nutritional research limit any definite conclusions on the effects of food items on specific health areas. This is why our approach blends recommendations from nutritional research with plausible mechanisms and focuses on overall diet quality rather than individual ingredients and other rigid parameters.

Reference lists tend to be wordy, indigestible and time-consuming. We are currently working to make references more visual and easy to understand, so you can simply and quickly review how we conducted our research and understand why this is a trusted source of information for you to rely on.

Fruits contain a wide variety of vitamins and phytonutrients, such as flavonoids. They can benefit the skin by reducing inflammation and oxidative stress. This study found that people who ate more fruit were less likely to have a skin condition than those who had less fruit.

The Journal of investigative dermatology - Association between Diet and Seborrheic Dermatitis: A Cross-Sectional Study - Sanders et al. (2019)

Kale contains a variety of nutrients, including glucoraphanin, which can enhance the production of essential skin components, such as collagen and hyaluronic acid. This study found that participants who had kale each day had increased skin moisture and decreased skin dryness compared to controls. Try other cruciferous vegetables with similar benefits, such as brussels, rocket leaves, cabbage and cauliflower.

Japanese pharmacology and therapeutics - Effects of kale containing glucoraphanin on skin conditions in healthy female subjects with skin dryness - Ohno et al. (2018)

Yoghurt is a natural source of probiotics that may promote skin health via the gut-skin axis by modulating the microorganisms that reside in our gut. This study combined results from 3 studies and found that yoghurt improved skin health and function.

Journal of alternative and complementary medicine - Effects of Fermented Dairy Products on Skin: A Systematic Review - Vaughn (2015)

Lingonberries and amla fruit both contain high concentrations of polyphenols, such as resveratrol and quercetin. They can improve skin function by reducing oxidative stress which prevents cellular damage and inflammation and promoting the production of collagen, a major skin component. This intervention study found an association between daily intake of lingonberry and amla fruit extract and improved skin function. Try other berries with similar benefits, such as blueberries, blackcurrants and raspberries.

Biotechnology and applied biochemistry - Oral intake of lingonberry and amla fruit extract improves skin conditions in healthy female subjects - Uchiyama et al. (2019)

Zinc is an essential mineral found in nuts, seeds, legumes and animal products. It is used by our bodies to support the normal functioning of skin cells, such as keratinocytes, and reduce inflammation, involved in many skin conditions. This study methodologically summarised the results of 22 studies including 1667 participants. They found that supplementation with zinc was beneficial for acne and hidradenitis suppurativa, but remained unclear for other skin conditions.

American journal of clinical dermatology - Effects of Zinc Supplementation on Inflammatory Skin Diseases - Dhaliwal et al. (2020)

Omega 3 fatty acids are essential nutrients that must be obtained from the diet. They have important functions in healthy skin by regulating inflammation and protecting against UV radiations. Studies investigating the effects of omega 3 fatty acids on skin conditions found mixed results: some found that omega-3 fatty acids improved skin symptoms, while others found no effects.

BMC complementary and alternative medicine - Effects of fish oil supplement on psoriasis: a meta-analysis of randomized controlled trials - Yang et al. (2019)

Clinical rheumatology - Efficacy of ω-3 supplementation in patients with psoriasis - Clark et al. (2019)

International journal of rheumatic diseases - Effect of omega-3 fatty acids on disease severity in patients with psoriasis: A systematic review - Upala et al. (2017)

Fruit and vegetables are rich sources of fibre, vitamins and minerals, antioxidants, flavonoids and phytochemicals. This nutrient content has protective effects against mental illnesses, such as depression. They can protect our brain cells against oxidative stress and contribute to the synthesis of neurotransmitters, such as serotonin. Several studies found that people with a higher intake of fruit and/or vegetables had a lower risk of depression compared to participants with a lower intake.

British journal of nutrition - Fruit and vegetable consumption and risk of depression - Saghafian et al. (2018)

Fish is a rich source of omega-3 fatty acids. Adding fish to our diet can support our mental health by regulating the activity of brain chemical messengers, reducing inflammation and oxidative stress. Research studies found that people with the highest fish consumption were less likely to develop depression compared to those with the lowest fish consumption.

Asia-Pacific psychiatry - Fish consumption and risk of depression: Epidemiological evidence from prospective studies - Yang et al. (2018)

Vitamin D is a nutrient critical for human survival that is found in fish and eggs. It may support our mental health by activating brain receptors involved in behaviour, stimulating the release of proteins involved in brain function and protecting the brain against oxidative damage and inflammation. Several studies found that vitamin D supplementation improved depressive symptoms in various cohorts, although some contradiction remains.

Journal of postgraduate medicine - Efficacy of vitamin D supplementation in major depression - Vellekkatt et al. (2019)

Diabetes & metabolic syndrome - Effects of vitamin D supplementation on depressive symptoms in type 2 diabetes mellitus patients - Omidian et al. (2019)

Progress in neuro-psychopharmacology & biological psychiatry - The effects of vitamin D supplementation on mental health, and biomarkers of inflammation and oxidative stress in patients with psychiatric disorders - Jamilian et al. (2019)

Jama - Effect of long-term vitamin D3 supplementation vs placebo on risk of depression or clinically relevant depressive symptoms and on change in mood scores - Okereke et al. (2020)

Iron is an essential dietary mineral present in a wide variety of foods, such as beans, lentils, nuts, seeds, red meat, tofu and dark leafy greens. It can support our mental health by influencing the levels of major receptors in brain tissues and the synthesis of brain chemical messengers, such as dopamine and serotonin. A few studies have found an association between dietary iron intake and decreased risk of depression.

Psychiatry research - Dietary zinc and iron intake and risk of depression - Li et al. (2017)

Zinc is an essential mineral found in nuts, seeds, legumes and animal products. It could support mental health by reducing brain inflammation, promoting neuronal plasticity and regulating the activity of brain chemical messengers, such as glutamate. Several observational studies found that people with a higher dietary zinc intake had a decreased risk of depression, compared to people with a lower intake.

Psychiatry research - Dietary zinc and iron intake and risk of depression - Li et al. (2017)

Magnesium is an essential mineral found in nuts, seeds and leafy vegetables. It can help protect our nervous system by regulating our stress response system, influencing the production of brain chemical messengers, reducing inflammation and protecting neurons against cell death. Several observational studies found that participants with a higher dietary magnesium intake showed a decreased risk of depression, compared to participants with a lower intake.

The Australian and New Zealand journal of psychiatry - Dietary magnesium and calcium intake and risk of depression in the general population - Li et al. (2017)

Various nutrients included in our diets, such as those found in fruits, vegetables and whole grains, can decrease inflammatory chemicals in our body. These can help reduce chronic inflammation which can help protect the brain, regulate the production of major brain chemicals and improve neuronal plasticity. Consistent evidence found that people on the most pro-inflammatory diet had an increased risk of depression diagnosis or symptoms, compared to those on an anti-inflammatory diet.

Clinical nutrition - An anti-inflammatory diet as a potential intervention for depressive disorders - Tolkien et al. (2019)

The Mediterranean diet is an eating pattern mainly composed of olive oil, nuts, fruit, vegetable, legumes, cereals and fish. The wide variety of nutrients contained in these foods may promote mental health by modulating the microbiome-gut-brain axis, promoting blood flow, improving metabolic health and reducing oxidative stress and inflammation. Several observational studies found a robust association between higher adherence to a Mediterranean diet and a lower risk of depression. Some studies also found lower symptoms of depression and anxiety.

Molecular psychiatry - Healthy dietary indices and risk of depressive outcomes - Lassale et al. (2019)

Annals of neurology - Mediterranean diet, stroke, cognitive impairment, and depression - Psaltopoulou et al. (2013)

Nutritional neuroscience - A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression - Parletta et al. (2019)

PloS one - A brief diet intervention can reduce symptoms of depression in young adults - Francis et al. (2019)

Curcumin is the main active compound of Turmeric, a spice that comes from the stem of the Curcuma longa plant. It may benefit the brain by regulating inflammation, reducing oxidative stress and disrupting the formation, accumulation, and toxicity of amyloid plaques in the brain. This intervention study found that participants who had curcumin daily improved their memory and attention performances, compared to the placebo group.

The American journal of geriatric psychiatry - Memory and Brain Amyloid and Tau Effects of a Bioavailable Form of Curcumin in Non-Demented Adults - Small et al. (2018)

Manganese is an essential mineral found in whole grains, tea and leafy vegetables. It plays a key role in the nervous system by influencing several proteins and enzymes involved in antioxidant defence, energy metabolism and immune function. Several studies found that people with Alzheimer’s disease had lower serum manganese levels compared with healthy controls.

Nutrients - Association of Serum Manganese Levels with Alzheimer's Disease and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis - Du et al. (2017)

Carotenoids are naturally occurring plant pigments found in a variety of fruits and vegetables including carrots, pumpkin, squash, tangerines, sweet potatoes, and kale. They can promote brain health by facilitating the connection between brain cells and reducing brain inflammation and oxidative stress, which can sharpen neuronal activity and protect the brain against neurodegeneration. This intervention study found participants taking daily carotenoids showed improved memory scores compared to the placebo group.

Journal of Alzheimer's disease - Supplemental Retinal Carotenoids Enhance Memory in Healthy Individuals with Low Levels of Macular Pigment in A Randomized, Double-Blind, Placebo-Controlled Clinical Trial - Power et al. (2018)

Vitamin C is an essential vitamin found in a variety of fruits and vegetables, such as kiwi, grapefruits, oranges and broccoli. It plays an important role in the brain by modulating the release of brain chemical messengers and protecting brain cells from free radical damage. There is some evidence suggesting the role of vitamin C in improving cognitive function.

The Cochrane database of systematic reviews - Vitamin and mineral supplementation for maintaining cognitive function in cognitively healthy people in mid and late life - Rutjes et al. (2018)

Omega-3 fatty acids are essential nutrients that can support brain health by decreasing the production of pro-inflammatory chemicals which may influence the levels of major neurotransmitters. Several observational studies found that the adoption of a diet enriched with omega-3 fatty acids decreased the risk of Parkinson’s and Alzheimer’s disease. Intervention studies found conflicting results with some finding no protective effect, which highlights the need for further research.

International journal of molecular sciences - Omega-3 Fatty Acids and Neurodegenerative Diseases - Avallone et al. (2019)

Fish is a major source of two types of omega-3 fatty acids called DHA and EPA. They play an important role in brain function, reducing inflammation and regulating blood pressure which may have a preventive effect on the risk of dementia. Several studies found that people who consumed fish had a lower risk of dementia compared to those who consumed no fish.

Public health nutrition - Association between fish consumption and risk of dementia - Bakre et al. (2018)

Cocoa is rich in a phytonutrient called flavanol. Including it in our diet may help protect against age-related cognitive dysfunction by increasing blood flow to the brain, promoting neuronal survival, improving glucose metabolism and protecting against neurodegeneration and neuroinflammation. This intervention study found that daily consumption of cocoa flavanol improved cognitive performance in a group of healthy elderly adults. They also observed a reduction in insulin resistance, which suggests a role of glucose metabolism in modulating cognitive function.

The American journal of clinical nutrition - Cocoa flavanol consumption improves cognitive function, blood pressure control, and metabolic profile in elderly subjects - Mastroiacovo et al. (2015)

Spearmint is high in polyphenols including rosmarinic acid. They are thought to improve cognitive function by reducing inflammation and oxidative stress in brain cells. This intervention study found that participants who had 900 mg spearmint extract each day improved the quality of working memory by 15% and spatial working memory by 9% compared to placebo.

Journal of alternative and complementary medicine - Spearmint Extract Improves Working Memory in Men and Women with Age-Associated Memory Impairment - Herrlinger et al. (2018)

Cherries are a rich source of plant chemicals, called flavonoids. They may help protect against neurodegenerative diseases and improve cognitive performance in older adults by protecting neurons against inflammation, supporting neuronal function and increasing blood flow to the brain. This intervention study found that participants who consumed cherry juice daily improved their verbal fluency and memory scores, compared to controls.

European journal of nutrition - Consumption of anthocyanin-rich cherry juice for 12 weeks improves memory and cognition in older adults with mild-to-moderate dementia - Kent et al. (2017)

Peanuts are a rich source of polyphenols, such as resveratrol and flavonoids, and nutrients such as folate, vitamin E, magnesium and potassium. A diet that includes peanuts may improve cognitive function by improving blood flow to the brain and exerting anti-inflammatory, antioxidant, or lipid-lowering effects. This intervention study found that regular peanut consumption improved blood flow to the brain and some cognitive performances in a group of 61 older adults.

Nutritional neuroscience - Cerebrovascular and cognitive benefits of high-oleic peanut consumption in healthy overweight middle-aged adults - Barbour et al. (2017)

Eggs are a major dietary source of choline, an essential nutrient that is involved in the synthesis of brain chemical messengers, such as acetylcholine. This study looked at the diets, dementia risk and cognitive performance of 2,497 men from Finland. They found that participants with higher egg intake had a lower risk of dementia and performed better in cognitive tests.

The American journal of clinical nutrition - Associations of dietary choline intake with risk of incident dementia and with cognitive performance - Ylilauri et al. (2019)

A traditional eating pattern found among populations living in the Mediterranean Basin during the 1950s and 60s.

It includes:

• Natural fats, such as extra virgin olive oil and nuts, containing monounsaturated fats and a variety of polyphenols that can exert cardioprotective effects

• Minimally processed, locally grown, vegetables, fruits, legumes and cereals

• Fish and shellfish in moderation

• Meat in low amounts

The nutrient content in these foods works together to promote heart health by reducing inflammation, oxidative stress and protecting against the formation of plaques in our arteries which can lead to heart disease.

A recent study methodologically reviewed and summarised 45 studies looking at the effects of the Mediterranean diet on heart health. They found that better conformity with the Mediterranean diet was associated with better cardiovascular outcomes. These benefits were seen in Mediterranean and non-Mediterranean populations. This is an important finding as it addresses concerns of bias related to nostalgic and geographic reasons.

Circulation research - The Mediterranean diet and cardiovascular health: A critical review. Circulation research - Martínez-González et al. (2019)

We calculated the overall inflammatory score for each recipe to ensure the amounts and ingredients included were associated with decreased inflammation.

A tool that provides scores indicating the inflammatory potential of foods, ranging from strongly pro-inflammatory to strongly anti-inflammatory.

Public health nutrition - Designing and developing a literature-derived, population-based dietary inflammatory index - Shivappa et al. (2014)