Plant Based Nutrition
Updated: Oct 22, 2020
We have all heard that eating a plant based diet is a game changer, right? Eating plant based is booming at the moment, and comes up in conversation more often than not; and for good reason. Adding more plants into your diet has many benefits as they are high in fibre and micronutrient dense. This can have many positive effects on your cardiovascular, gut and immune health. However, while going plant based could be great, it also could have a detrimental effect on other health factors.
There are a number of key nutrients that are often lacking in a plant based diet. These need more attention when cooking and planning meals as they play a huge role in our health and well-being.
Many approach plant based eating as just cutting out meat and dairy, where protein is often the main nutrient that is missed. Getting enough plant based protein is very achievable but it does require an understanding of what sources will give you quality protein and enough of it. Generally, aiming for 1.2-1.6g/kg of protein per day will meet an adult's needs, but it is important this is spread across the day in ~0.3g/kg amounts for optimal metabolism and satiety.
What is a high quality protein source?
Protein is a chain of amino acids (AAs). There are 20 different AAs, where the amount and type of these AAs within a chain determines the quality of the protein. Animal sources of protein contain a full set of essential amino acids (EAAs), making it a high quality protein source as humans are unable to produce these naturally. On the other hand, plants often lack at least one of these AAs, where we would consider it an incomplete protein. However, eating a variety of plant protein sources can make up for this. If one source is lacking in one of these AAs, then another may provide it. Plant proteins such as rice and pea both have an incomplete profile as a single product, but often used together in supplements as a compete plant protein powder.
The most common amino acid that is missing in plants is Leucine, which is vital for muscle protein synthesis. Leucine acts as a main ‘trigger’ to get these processes going. Including plant based foods that provide a rich source of Leucine is important, such as:
In addition to the quality, plants contain much less overall protein than animal sources. A good example of this is plant milks. When comparing plant milks to cow’s milk there is a difference in the protein per serve (250ml). Blue milk contains 8.3g of protein whereas oat milk contains 2.5g and almond even lower at 1.4g. Soy milk, however, is a good alternative with 8g. It is important to remember that alternatives will not have the same amount of nutrients. Continuing with plant milks, calcium can also be lacking if they aren’t fortified. Read more information on this below.
Overall, plant based diets can contain adequate protein, but it is important that a variety of options are consumed. Planning is essential to ensure that our protein targets are met (in both meals and snacks) as well as obtaining them from a range of sources over the day.
The main role iron plays is in our red blood cells in the delivery of oxygen, as well as supporting the immune system and cognitive function. Iron deficiency is something that can significantly impair performance and overall quality of life.
Signs of iron deficiency are:
• Decreased cognitive function
• Decreased performance
• Change in mood
• Impaired immune function
• May be associated with amenorrhea
• Iron status may be low if blood results are:
- Haemoglobin = <115g/L female, <135g/L male
- Serum Ferritin = <15ug/L female, <30ug/L male
Due to females having periods, they are at greater risk of iron deficiency and therefore have a higher requirement. Adult females need 18mg per day compared to 8mg per day for Men. However, eating a vegetarian/vegan diet increases your requirements further (1.8x higher than their omnivorous counterpart). This is due to plants containing less iron overall, and the ability to absorb that iron is significantly reduced. This makes iron a key concern in females who are following a plant based diet and especially those who are exercising regularly.
Why do vegetarians and vegans absorb less iron?
There are two types of iron; haem iron and non-haem. Haem iron comes from animal products and is much more readily absorbable. Non-haem iron is found in plants and unfortunately is harder to absorb. On top of this, some plant foods contain compounds that inhibit this absorption as well. This is why those eating a plant based diet have a higher iron requirement and need to be aware of how to match their foods to enhance absorption – especially when you are susceptible to deficiency.
Tips for enhancing iron absorption:
Pair iron rich foods with foods high in Vitamin C as it aids in absorption. See the list below for options.
Onion and Garlic also help absorption. These are both an easy add on to many main meals.
Drinking tea, coffee, beer or wine with a meal as they contain tannins which impair iron absorption. Ensure you have these beverages at least 30 mins before or after to reduce the impact.
Having high calcium foods in meals where the focus is for iron. Calcium interferes with the pathways in which iron takes to be absorbed.
Plant sources of iron
B12 is an essential vitamin which is vital for our nerves, blood cells, as well as playing a part in making our DNA. Adults need 2.4ug of B12 per day. Unfortunately, there are no good plant based sources of B12. Some fermented products and plants have B12, as well as fortified foods, but none worthy of being labelled a ‘good source’. It is recommended that a B12 supplement is used (one of the few times that I will suggest a supplement over a food first approach).
There are 3 types of supplements you can take which include:
These supplements are VITAL if you are completely plant based, if you consume animal products such as dairy and eggs, supplementation may not be required. Please discuss vitamin B12 options with your GP.
Dairy is our major source of calcium, so where can you get it from when you go dairy free? There is an increased range of dairy alternatives nowadays made from soy, almonds, coconuts, oats, cashews and rice that are fortified with calcium. When looking for milk or dairy alternatives, read the label to ensure that these have adequate calcium. Adults need 1000mg of calcium per day. If a plant milk has at least 250mg of calcium per serve, this would be a good source and will likely mean they have fortified it with calcium.
Meat and dairy are a good dietary sources of Zinc, so this is an important nutrient to note. Adult males require 14mg per day and adult females require 8mg per day. Zinc absorption is similar to iron, that requirements are higher in plant based individuals. It is further recommended that those following a strict vegetarian/vegan diet have 50% more than their omnivorous counterpart. Males have higher requirements for zinc as it is lost in sperm.
Zinc is an important mineral, especially in those that exercise, as it is a key component in many enzymes and also plays a crucial role in our immune system.
Putting it all together
Planning out your meals and snacks is a good idea to make sure you include sources of these important nutrients each day. Below is a few options for meals and snacks that you can add to your repertoire. For those who are doing vigorous exercise regularly, adding a plant protein powder will also be beneficial in boosting your protein intake and help you with recovery and performance.
Alter these to suit your dietary requirements, preferences and budget. Also, you can add other plant protein sources to these recipes to ensure that you are hitting your protein requirements.
(click on them to see the recipes)
If you have changed to more plant based or have committed fully to a vegan diet, it is important to also take note of how you are feeling. Have you noticed you are tired more often, your exercise performance has dropped or are you struggling to focus at work? These can all be signs of deficiencies. If you have any of these symptoms regularly or have a history of deficiencies, then booking an appointment with Conrad will be very beneficial. You will be able to get individualised advice and support to ensure you thrive on a plant based diet.
Do you need to be entirely vegan?
Everyone has their own reasons for going plant based, whether this is for ethical reasons, to support the environment or to improve the quality of your diet. No matter the reason, eating more plant based foods are a fantastic option for all of these. I do however, want to also stress that you can enjoy being plant based, while still being able to enjoy some animal products. You can still cook your favourite meat dish, order poached eggs for brunch and tuck into that cheese board. Don’t feel like you need to put a label on yourself and let it restrict you from the foods that you enjoy. If you still want to completely go plant based, it will be more difficult to reach all required nutrients, however it is possible when you put the effort in. Try including the food options shown throughout, if there are a few you haven't tried yet, give them a go. But overall, do what works and feels right for you.
Let’s not overcomplicate this eating thing.